workflows/tests: set DEBIAN_FRONTEND=noninteractive

Author: cho-m

.github/workflows/tests.yml

@@ -346,6 +346,8 @@ jobs:
         # All other images are built from our Homebrew Dockerfile.
         # This is the only one that needs to be set up manually.
         if: matrix.container == 'ubuntu:22.04'
+        env:
+          DEBIAN_FRONTEND: noninteractive
         run: |
           # Slimmed down version from the Homebrew Dockerfile
           apt-get update