upgrade pip before poetry install

Author: betaBison

.github/workflows/python-app.yml

@@ -44,7 +44,9 @@ jobs:
         key: venv-${{ runner.os }}-${{ hashFiles('**/poetry.lock') }}
     - name: Install dependencies
       if: steps.cached-poetry-dependencies.outputs.catch-hit != 'true'
-      run: poetry install
+      run: |
+        poetry run pip install --upgrade pip
+        poetry install
     # Install pandoc for building docs
     - name: Install pandoc for Ubuntu
       if: matrix.os == 'ubuntu-latest'