ubunut 20-04 is EOL (#220)

Author: dmarticus

.github/workflows/release.yaml

@@ -6,7 +6,7 @@ on:
 jobs:
     release:
         name: Publish release
-        runs-on: ubuntu-20.04
+        runs-on: ubuntu-latest
         env:
             TWINE_USERNAME: __token__
             TWINE_PASSWORD: ${{ secrets.PYPI_API_TOKEN }}