ci: Check for conflicts & valid python in early separate step

.github/workflows/server-tests-postgres.yml

@@ -48,6 +48,14 @@ jobs:
         with:
           python-version: '3.10'
 
+      - name: Check for valid Python & Merge Conflicts
+        run: |
+          python -m compileall -f "${GITHUB_WORKSPACE}"
+          if grep -lr --exclude-dir=node_modules "^<<<<<<< " "${GITHUB_WORKSPACE}"
+              then echo "Found merge conflicts"
+              exit 1
+          fi
+
       - name: Setup Node
         uses: actions/setup-node@v2
         with:
@@ -90,7 +98,6 @@ jobs:
           restore-keys: |
             ${{ runner.os }}-yarn-
 
-
       - name: Install
         run: bash ${GITHUB_WORKSPACE}/.github/helper/install.sh
         env: