Introducing CONTRIBUTING.md (#744)

Introducing CONTRIBUTING.md and changed related files (such as .github/pull_request_template.md and README.md).

.github/ISSUE_TEMPLATE/incorrect-parsing.md

@@ -8,10 +8,10 @@ assignees: ''
 ---
 
 <!-- DO NOT THROW THIS AWAY -->
-<!-- Fill out the FULL versions with patch versions -->
+<!-- Fill out the FULL versions with patch versions (e.g. 2.10.0) -->
 
- - PHP Version: 
- - PDFParser Version: 
+ - PHP Version:
+ - PDFParser Version:
 
 ### Description:
 

.github/pull_request_template.md

@@ -11,22 +11,4 @@
 
 # Checklist for code / configuration changes
 
-*In case you changed the code/configuration, please read each of the following checkboxes as they contain valuable information:*
-
-* [ ] Please add at least **one test case** (unit test, system test, ...) to demonstrate that the change is working. If existing code was changed, your tests cover these code parts as well.
-     By the way, you don't have to provide a full fledged PDF file to demonstrate a fix. Instead a unit test may be sufficient sometimes,
-     please have a look at [FontTest](https://github.com/smalot/pdfparser/blob/master/tests/PHPUnit/Unit/FontTest.php#L40) for example code.
-     Code changes without any tests are likely to be rejected. If you dont know how to write tests, no problem, tell us upfront and we may add them ourselves or discuss other ways.
-* [ ] Please run **PHP-CS-Fixer** before committing, to confirm with our coding styles. See https://github.com/smalot/pdfparser/blob/master/.php-cs-fixer.php for more information about our coding styles.
-* [ ] In case you **fix an existing issue**, please do one of the following:
-  * [ ] Write in this text something like `fixes #1234` to outline that you are providing a fix for the issue `#1234`.
-  * [ ] After the pull request was created, you will find on the right side a section called **Development**. There issues can be selected which will be closed after the your pull request got merged.
-* [ ] In case you changed internal behavior or functionality, please check our documentation to make sure these changes are **documented properly**: https://github.com/smalot/pdfparser/tree/master/doc
-* [ ] In case you want to discuss new ideas/changes and you are not sure, just create a pull request and mark it as **a draft**
-      (see [here](https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/proposing-changes-to-your-work-with-pull-requests/about-pull-requests#draft-pull-requests) for more information).
-      This will tell us, that it is not ready for merge, but you want to discuss certain issues.
-
-<!--
-Pull requests will be declined/rejected if one part of the continous integration pipeline fails. 
-We use the pipeline to make sure no regressions are introduced and existing code still runs as expected.
--->
+See [CONTRIBUTING.md] for all essential information about contributing.

CONTRIBUTING.md

@@ -0,0 +1,19 @@
+# Contributing
+
+**Please read the following text before creating a pull request.**
+
+This project is organized and supported by contributions from the community. Maintenance is done in our limited time.
+We welcome any pull request that contributes to PDFParser (code, documentation, ...).
+However, we would like to point out that you are initially responsible for a contribution.
+If you are new to dealing with pull requests, you can find more information at [Github documentation](https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/proposing-changes-to-your-work-with-pull-requests/about-pull-requests).
+Please don't just throw code at us and expect us to handle it.
+Nevertheless, we will support you and give you feedback.
+
+To make life easier for you and us, there is a Continuous Integration (CI) system that carries out software tests and performs a number of other tasks.
+The following points describe the relevant preparations/inputs for the CI system.
+All checks must be green, otherwise a pull request will not be accepted.
+* Please create an [issue](https://github.com/smalot/pdfparser/issues) before starting work on any significant changes.
+* We only accept code that is bundled with tests, regardless of whether it is a new function or a bug fix. This strengthens the code base and avoids later regressions. :exclamation: **If you don't know how to write a test, tell us upfront when you open the pull request and we might add them ourselves or discuss other ways**. This [Medium article](https://pguso.medium.com/a-beginners-guide-to-phpunit-writing-and-running-unit-tests-in-php-d0b23b96749f) might be a good starting point. Code changes without tests are very likely to be rejected.
+* Fix reported issues with the coding style. We use **PHP-CS-Fixer** for this. See [.php-cs-fixer.php](./.php-cs-fixer.php) for more information about our coding styles. [Developer.md](./doc/Developer.md) contains more information about this topic.
+* If you are fixing an **existing error**, refer to it in the introduction text of the pull request. For example, if you created a fix for issue `#1234` write the following Markdown: `fixes #1234`.
+* In case you have changed **internal behavior/functionality**, check our documentation to make sure these changes are **correctly documented**: https://github.com/smalot/pdfparser/tree/master/doc

README.md

@@ -10,6 +10,7 @@ The `smalot/pdfparser` is a standalone PHP package that provides various tools t
 
 This library is under **active maintenance**.
 There is no active development by the author of this library (at the moment), but we welcome any pull request adding/extending functionality!
+See [CONTRIBUTING.md](./CONTRIBUTING.md) for further information about how to contribute.
 
 ## Features