Update to require minimum PHP 8

[Namoshek]

Since PHP 7 is end of life for a while now (and PHP 8.0 is still supported until midnight 😉), the minimum required PHP version is now 8.0.

As part of this change, the redundant PhpDocs have been removed and some method invocations have been replaced. But all in all, this upgrade does not introduce too many changes.

[github-actions]

Dependency Review

The following issues were found:

• ✅ 0 vulnerable package(s)
• ✅ 0 package(s) with incompatible licenses
• ✅ 0 package(s) with invalid SPDX license definitions
• ⚠️ 1 package(s) with unknown licenses.

See the Details below.

License Issues

composer.json

Package	Version	License	Issue Type
php	>= 8.0, < 9.0	Null	Unknown License

Scanned Manifest Files

composer.json

• php@>= 8.0, < 9.0
• php@>= 7.4|^8.0, < 8.0.0