Bump actions/setup-python from 2 to 3 (#300)

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] <[email protected]>

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

Author: dependabot[bot]

.github/workflows/main.yml

@@ -20,7 +20,7 @@ jobs:
     - uses: actions/checkout@v2
       with:
         fetch-depth: 0
-    - uses: actions/setup-python@v2
+    - uses: actions/setup-python@v3
       with:
         python-version: '3.9'
     - name: Install GitHub matcher for ActionLint checker
@@ -61,7 +61,7 @@ jobs:
     - uses: actions/checkout@v2
       with:
         fetch-depth: 0
-    - uses: actions/setup-python@v2
+    - uses: actions/setup-python@v3
       with:
         python-version: ${{ matrix.python-version }}
     - name: Install dependencies