Use alternative JinjaSQL branch/build compatible with jinja2>=3.0. (#77)

* Use alternative JinjaSQL branch/build that has been upgraded to be compatible with jinja2>=3.0

Author: James Robinson

.github/workflows/main.yaml

@@ -33,9 +33,8 @@ jobs:
         uses: actions/checkout@v2
 
       - name: Install poetry
-        uses: abatilo/[email protected]
-        with:
-          poetry-version: 1.2.2
+        shell: bash
+        run: curl -sSL https://install.python-poetry.org | POETRY_VERSION=1.2.2 python3 -
 
       - name: Set up Python ${{ matrix.python-version }}
         id: setup_python