Invoke setup-python-poetry with explicit version

Not sure about this. It's hardcoding versions everywhere.

.github/workflows/tests.yml

@@ -36,6 +36,7 @@ jobs:
       - uses: matrix-org/setup-python-poetry@v1
         with:
           python-version: "3.x"
+          poetry-version: "1.3.2"
           extras: "all"
       - run: poetry run scripts-dev/generate_sample_config.sh --check
       - run: poetry run scripts-dev/config-lint.sh
@@ -86,6 +87,7 @@ jobs:
           ref: ${{ github.event.pull_request.head.sha }}
       - uses: matrix-org/setup-python-poetry@v1
         with:
+          poetry-version: "1.3.2"
           extras: "all"
       - run: poetry run scripts-dev/check_pydantic_models.py
 
@@ -217,6 +219,7 @@ jobs:
       - uses: matrix-org/setup-python-poetry@v1
         with:
           python-version: ${{ matrix.job.python-version }}
+          poetry-version: "1.3.2"
           extras: ${{ matrix.job.extras }}
       - name: Await PostgreSQL
         if: ${{ matrix.job.postgres-version }}
@@ -292,6 +295,7 @@ jobs:
       - uses: matrix-org/setup-python-poetry@v1
         with:
           python-version: '3.7'
+          poetry-version: "1.3.2"
           extras: "all test"
 
       - run: poetry run trial -j6 tests
@@ -326,6 +330,7 @@ jobs:
       - uses: matrix-org/setup-python-poetry@v1
         with:
           python-version: ${{ matrix.python-version }}
+          poetry-version: "1.3.2"
           extras: ${{ matrix.extras }}
       - run: poetry run trial --jobs=2 tests
       - name: Dump logs
@@ -417,6 +422,7 @@ jobs:
       - run: sudo apt-get -qq install xmlsec1 postgresql-client
       - uses: matrix-org/setup-python-poetry@v1
         with:
+          poetry-version: "1.3.2"
           extras: "postgres"
       - run: .ci/scripts/test_export_data_command.sh
         env:
@@ -468,6 +474,7 @@ jobs:
       - uses: matrix-org/setup-python-poetry@v1
         with:
           python-version: ${{ matrix.python-version }}
+          poetry-version: "1.3.2"
           extras: "postgres"
       - run: .ci/scripts/test_synapse_port_db.sh
         id: run_tester_script