Add postgis to CI setup

.github/workflows/ci.yml

@@ -25,7 +25,7 @@ jobs:
       # Label used to access the service container
       postgres:
         # Docker Hub image
-        image: postgres:16.2-alpine
+        image: postgis
         # Provide the password for postgres
         env:
           POSTGRES_USER: postgres
@@ -45,10 +45,6 @@ jobs:
         with:
           fetch-depth: 0  # Shallow clones should be disabled for a better relevancy of sonarcloud analysis
 
-      - name: Install dependencies
-        run: |
-          sudo apt-get install -qq postgis postgresql-postgis
-
       # We don't have to specify the ruby version, or grab it from .ruby-verion. This action supports reading the
       # version from .ruby-version itself
       - name: Install Ruby