Trim down list of python-version

With a large number of the versions of Python specified not being
supported with GitHub Actions, trim it down to the major versions, and
add in 3.11 for good measure.

.github/workflows/pythonpackage.yml

@@ -18,7 +18,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: [3.7, 3.7.5, 3.7.12, 3.8, 3.8.0, 3.8.11, 3.8, 3.9, 3.9.0, 3.9.7, "3.10"]
+        python-version: [3.7, 3.8, 3.9, "3.10", "3.11"]
 
     steps:
     - uses: actions/checkout@v3