Bump actions/setup-python from 2 to 3 (#250)

Bumps [actions/setup-python](https://github.com/actions/setup-python) from 2 to 3.
- [Release notes](https://github.com/actions/setup-python/releases)
- [Commits](actions/setup-python@v2...v3)

---
updated-dependencies:
- dependency-name: actions/setup-python
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

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

.github/workflows/tests.yml

@@ -30,7 +30,7 @@ jobs:
           fetch-depth: 0
 
       - name: Setup Python
-        uses: actions/setup-python@v2
+        uses: actions/setup-python@v3
         with:
           python-version: ${{ matrix.python-version }}
 
@@ -59,7 +59,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Setup Python
-        uses: actions/setup-python@v2
+        uses: actions/setup-python@v3
         with:
           python-version: "3.9"
       - name: Finish coverage collection
@@ -78,7 +78,7 @@ jobs:
           fetch-depth: 0
 
       - name: Setup Python
-        uses: actions/setup-python@v2
+        uses: actions/setup-python@v3
         with:
           python-version: "3.9"
 
@@ -96,7 +96,7 @@ jobs:
       - uses: actions/checkout@v2
         with:
           fetch-depth: 0
-      - uses: actions/setup-python@v2
+      - uses: actions/setup-python@v3
         name: Install Python
         with:
           python-version: "3.9"