Another fix

Author: roxanneskelly

.github/workflows/ci.yaml

@@ -12,10 +12,9 @@ jobs:
     strategy:
       matrix:
         python-version: ['2.7', '3.7', '3.8', '3.10']
-        container: ["python:2.7", "python:3.7", "python:3.8", "python:3.10"]
     runs-on: [ubuntu-latest]
     container:
-      image: ${{ matrix.containert }}
+      image: "python:${{ matrix.python-version }}"
     env:
       PYTHON: ${{ matrix.python-version }}
     steps: