gci: Add a test for the postgres backend

.github/workflows/ci.yaml

@@ -203,6 +203,14 @@ jobs:
             EXPERIMENTAL_FEATURES: 1
             TEST_DB_PROVIDER: sqlite3
             COMPILER: clang
+          # And of course we want to test postgres too
+          - NAME: postgres
+            CFG: gcc-dev1-exp1
+            DEVELOPER: 1
+            EXPERIMENTAL_FEATURES: 1
+            COMPILER: gcc
+            TEST_DB_PROVIDER: postgres
+
     steps:
       - name: Checkout
         uses: actions/checkout@v3
@@ -236,6 +244,7 @@ jobs:
           SLOW_MACHINE: 1
           PYTEST_PAR: 10
           TEST_DEBUG: 1
+          TEST_DB_PROVIDER: ${{ matrix.TEST_DB_PROVIDER }}
         run: |
           tar -xaf cln-${CFG}.tar.bz2
           poetry run pytest tests/ -vvv -n ${PYTEST_PAR} ${PYTEST_OPTS}
@@ -290,6 +299,7 @@ jobs:
 
       - name: Install dependencies
         run: |
+          sudo apt-get install -yyq valgrind
           pip3 install --user pip wheel poetry
           poetry install
 
@@ -299,7 +309,10 @@ jobs:
       - name: Download build
         uses: actions/download-artifact@v3
         with:
-          name: cln-${ CFG }.tar.bz2
+          name: cln-gcc-dev1-exp1.tar.bz2
+
+      - name: Unpack build
+        run: tar -xvjf cln-gcc-dev1-exp1.tar.bz2
 
       - name: Test
         env:
@@ -307,9 +320,9 @@ jobs:
           SLOW_MACHINE: 1
           TEST_DEBUG: 1
         run: |
-          tar -xjf cln-${{ matrix.CFG }}.tar.bz2
-          sed -i 's/VALGRIND=0/VALGRIND=1/g' config.vars 
-          poetry run pytest tests/ -vvv -n 5 ${PYTEST_OPTS}  ${{ matrix.PYTEST_OPTS }}
+
+          sed -i 's/VALGRIND=0/VALGRIND=1/g' config.vars
+          poetry run pytest tests/ -vvv -n 3 ${PYTEST_OPTS}  ${{ matrix.PYTEST_OPTS }}
 
   gather:
     # A dummy task that depends on the full matrix of tests, and