chore: remove old python versions (#930)

* remove python 3.8 from package definition and build matric
* update github actions for consistency while we're at it
* tag version number

FIXES: APER-3885
FIXES: #858

.github/workflows/ci.yml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ['3.8', '3.12']
+        python-version: ['3.12']
         django-version: ['4.2']
     steps:
     - uses: actions/checkout@v4

.github/workflows/create_credentials_requirements_pr.yml

@@ -30,7 +30,7 @@ jobs:
 
       - uses: actions/setup-python@v5
         with:
-          python-version: "3.11"
+          python-version: "3.12"
           architecture: x64
 
       - name: upgrade requirements

edx_credentials_themes/__init__.py

@@ -1 +1 @@
-__version__ = '0.4.27'
+__version__ = '0.4.28'

setup.py

@@ -147,7 +147,6 @@ def get_version(*file_paths):
         'License :: Other/Proprietary License',
         'Natural Language :: English',
         'Programming Language :: Python',
-        'Programming Language :: Python :: 3.8',
         'Programming Language :: Python :: 3.12',
         'Framework :: Django',
         'Framework :: Django :: 4.2',