Add Python 3.13 and remove Python 3.7 from CI

3.13 is the latest version and 3.7 has reached EOL in 2023-06.

Author: mweinelt

.github/workflows/python-package.yml

@@ -18,7 +18,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ['3.7', '3.8', '3.9', '3.10', '3.11', '3.12']
+        python-version: ['3.8', '3.9', '3.10', '3.11', '3.12', '3.13']
 
     steps:
     - uses: actions/checkout@v2