⬆️ Bump actions/setup-python from 2 to 4 (#80)

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Chris Sewell <chrisj_sewell@hotmail.com>

Author: dependabot[bot]

.github/workflows/tests.yml

@@ -19,7 +19,7 @@ jobs:
     steps:
     - uses: actions/checkout@v2
     - name: Set up Python 3.8
-      uses: actions/setup-python@v2
+      uses: actions/setup-python@v4
       with:
         python-version: 3.8
     - uses: pre-commit/action@v3.0.0
@@ -35,7 +35,7 @@ jobs:
     steps:
     - uses: actions/checkout@v2
     - name: Set up Python ${{ matrix.python-version }}
-      uses: actions/setup-python@v2
+      uses: actions/setup-python@v4
       with:
         python-version: ${{ matrix.python-version }}
     - name: Install dependencies
@@ -71,7 +71,7 @@ jobs:
     - name: Checkout source
       uses: actions/checkout@v2
     - name: Set up Python
-      uses: actions/setup-python@v2
+      uses: actions/setup-python@v4
       with:
         python-version: "3.8"
     - name: install flit