Cap python at 3.9.

Author: albop

.github/workflows/ci.yaml

@@ -9,7 +9,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: [ '3.7', '3.8', '3.9', '3.10']
+        python-version: [ '3.7', '3.8', '3.9']
 
     name: Test Interpolation.py (Python ${{ matrix.python-version }})
     steps: