Remove pip caching in GitHub Actions workflow

The caching of pip dependencies in the GitHub Actions workflow file has been removed. This adjustment may slightly impact performance, however it ensures a fresh pip environment for each run, reducing potential inconsistencies or errors.

.github/workflows/pythonapp.yml

@@ -25,7 +25,6 @@ jobs:
       uses: actions/setup-python@v4
       with:
         python-version: ${{ matrix.python-version }}
-        cache: 'pip' # caching pip dependencies will speed up subsequent runs
 
     - name: Install dependencies
       run: |