Bump actions/checkout from 1 to 3

Bumps [actions/checkout](https://github.com/actions/checkout) from 1 to 3.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v1...v3)

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

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/main.yml

@@ -14,7 +14,7 @@ jobs:
         python: ["3.7","3.8","3.10","3.11", "pypy-3.7"]
 
     steps:
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v3
     - name: Set up Python
       uses: actions/setup-python@v2
       with:
@@ -33,7 +33,7 @@ jobs:
     needs: tests
 
     steps:
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v3
     - name: Set up Python
       uses: actions/setup-python@v2
       with: