use quotes arround python version 3.10

Author: cjekel

.github/workflows/ci.yml

@@ -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, '3.10']
 
     steps:
     - uses: actions/checkout@v2

.github/workflows/cron.yml

@@ -11,7 +11,7 @@ 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, '3.10']
 
     steps:
     - uses: actions/checkout@v2