Run on ubuntu-20.04

Author: shayonj

.github/workflows/ci.yaml

@@ -14,7 +14,7 @@ concurrency:
 
 jobs:
   rspec:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     timeout-minutes: 30
     name: Ruby ${{ matrix.ruby }} - PG ${{ matrix.pg.from }} -> PG ${{ matrix.pg.to }}
     strategy:
@@ -96,7 +96,7 @@ jobs:
         run: bundle exec rspec
   build-push-image:
     if: startsWith(github.ref, 'refs/tags/v')
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     timeout-minutes: 30
     needs: [rspec]
     steps: