5.1.0 SF6 and PHP8 support

What's Changed

• Fixing broken link to GSSP-example Defaultcontroller by @KarsanHAM in #45
• Replace Travis with GHA by @MKodde in #38
• Upgrade PHP dependencies by @MKodde in #39
• Move QA scripts to ci/qa folder by @MKodde in #40
• Improve code quality by addressing static analysis issues from PHPStan by @MKodde in #41

New Contributors

• @KarsanHAM made their first contribution in #45

Full Changelog: 5.0.0...5.1.0