Use ubuntu-20.04 for acceptance tests (#293)

Author: pskrbasu

.github/workflows/test.yml

@@ -5,7 +5,7 @@ on:
 jobs:
   build_and_test:
     name: Build and run tests
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
       - name: Set up Go
         uses: actions/setup-go@v3