fix CI

Author: terencehonles

.github/workflows/github-actions.yml

@@ -55,7 +55,7 @@ jobs:
   test:
     # Test suite run against recent python versions
     # and against a few combination of MongoDB and pymongo
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     strategy:
       fail-fast: false
       matrix: