Drop support for EOL Python 3.7 (#1065)

* Add python_requires to help pip

* Update supported versions in tox.ini

* Upgrade Python syntax with pyupgrade --py37-plus

* Bump GitHub Actions

* Add Python 3.11 and 3.12 to CI

* Remove six dependency

* Remove redundant dependencies

* Remove redudant Python 3.5 code

* Drop support for EOL Python 3.7

* Upgrade Python syntax with pyupgrade --py38-plus

* Update CHANGELOG

* More f-strings

---------

Co-authored-by: Hugo van Kemenade <hugovk@users.noreply.github.com>

.github/workflows/pull_request.yml

@@ -8,8 +8,8 @@ jobs:
   changelog:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v1
-      - uses: dangoslen/changelog-enforcer@v1.1.1
+      - uses: actions/checkout@v4
+      - uses: dangoslen/changelog-enforcer@v3.5.1
         with:
           changeLogPath: 'CHANGELOG.md'
           skipLabel: 'skip-changelog'