CI: Fix the export-data job to run under poetry (#12418)

Co-authored-by: Patrick Cloke <clokep@users.noreply.github.com>

.github/workflows/tests.yml

@@ -270,9 +270,10 @@ jobs:
     steps:
       - uses: actions/checkout@v2
       - run: sudo apt-get -qq install xmlsec1
-      - uses: actions/setup-python@v2
+      - uses: matrix-org/setup-python-poetry@v1
         with:
-          python-version: "3.9"
+          python-version: ${{ matrix.python-version }}
+          extras: "postgres"
       - run: .ci/scripts/test_export_data_command.sh
 
   portdb: