Improve project structure for the sake of packaging

What's being changed:

• no functionality is added or removed.

Handle case when there is more/less than one Packt Free Learning offer

What's being changed:

• handle case when there is more/less than one Packt Free Learning offer,
• create list of unique user's Packt products.

Add oauth2client to requirements

What's being changed:

• missing oauth2client is added requirements,
• other dependencies are upgraded,
• GitHub Actions are used instead of Travis.

Whitelist +, #, ., - and – special characters

What's being changed:

• +, #, ., - and – special characters were excluded from downloaded file name - it should no longer happen.

Pass ReCAPTCHA solution to login request

What's being changed:

• ReCAPTCHA solution is being passed to login request due to changes in Packt API.

Update packt dependencies to support Python 3.8

v1.4.3

Release 1.4.3

Wait until download URLs are available after claiming Packt product

v1.4.2

Release 1.4.2

Fix sending emails on Python 3.7

v1.4.1

Release 1.4.1

Read configuration file granularly

What's being changed:

• download configuration is not required when claiming products without downloading,
• AntiCaptcha key is not required to download Packt products.

Recover precheck logic to prevent reclaim

What's being changed:

• recover precheck logic to prevent reclaim,
• clean up files from unsuccessful downloads,
• drop support for Python 3.4.x.