Update workflow file

Author: learnforpractice

.github/workflows/python-app.yml

@@ -79,7 +79,6 @@ jobs:
         run: |
           python -m pip uninstall mixin-python -y;python -m pip install ./dist/${{ steps.whlfile.outputs.value }}
       - name: Test
-        if: ${{ matrix.os != 'windows-2019' }}
         working-directory: tests
         run: |
           python -m pip install -r ../requirements-dev.txt