Add automated test workflow

Author: jnasbyupgrade

.github/workflows/ci.yml

@@ -4,7 +4,7 @@ jobs:
   test:
     strategy:
       matrix:
-        pg: [17, 16, 15, 14, 13, 12, 11, 10, 9.6, 9.5, 9.4, 9.3, 9.2]
+        pg: [18, 17, 16, 15, 14, 13, 12, 11, 10]
     name: 🐘 PostgreSQL ${{ matrix.pg }}
     runs-on: ubuntu-latest
     container: pgxn/pgxn-tools
@@ -14,4 +14,4 @@ jobs:
       - name: Check out the repo
         uses: actions/checkout@v4
       - name: Test on PostgreSQL ${{ matrix.pg }}
-        run: pg-build-test
+        run: make test PGUSER=postgres