Bug 1905521: Temporary fix for deprecated Postgres Docker image (#137)

Docker in Ubuntu 22.04 and 24.04 no longer supports version 1 docker images, which the Postgres 9 image we use to run tests is.  Long term fix is to up our minimum Postgres requirement to Postgres 12. Short term fix here is to run the Pg test on ubuntu-20.04 instead of ubuntu-latest.
a=dylan

.github/workflows/ci.yml

@@ -49,15 +49,15 @@ jobs:
         run: docker compose -f docker-compose.test-mariadb.yml run -e CI=1 bugzilla6.test test_bmo -q -f t/bmo/*.t
 
   test_bugzilla6_pg:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
       - uses: actions/checkout@v4
       - name: Install docker-compose
-        run: sudo apt update && sudo apt install -y docker-compose
+        run: sudo apt update && sudo apt install -y docker-compose docker.io
       - name: Build the Docker images
-        run: docker compose -f docker-compose.test-pg.yml build
+        run: docker-compose -f docker-compose.test-pg.yml build
       - name: Run bmo specific tests
-        run: docker compose -f docker-compose.test-pg.yml run -e CI=1 bugzilla6.test test_bmo -q -f t/bmo/*.t
+        run: docker-compose -f docker-compose.test-pg.yml run -e CI=1 bugzilla6.test test_bmo -q -f t/bmo/*.t
 
   test_bugzilla6_sqlite:
     runs-on: ubuntu-latest