Remove postgres service from github action [Resolves #899]

`testing.postgresql` runs `initdb` locally. The postgres service doesn't get used.

.github/workflows/test.yaml

@@ -4,22 +4,7 @@ on: [push]
 
 jobs:
   build:
-
     runs-on: ubuntu-latest
-    services:
-      # Label used to access the service container
-      postgres:
-        # Docker Hub image
-        image: postgres
-        # Provide the password for postgres
-        env:
-          POSTGRES_PASSWORD: postgres
-        # Set health checks to wait until postgres has started
-        options: >-
-          --health-cmd pg_isready
-          --health-interval 10s
-          --health-timeout 5s
-          --health-retries 5
     strategy:
       matrix:
         python-version: ['3.8', '3.9', '3.10']