Bump actions/checkout from 1 to 4 (#9)

Bumps [actions/checkout](https://github.com/actions/checkout) from 1 to 4.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v1...v4)

---
updated-dependencies:
- dependency-name: actions/checkout
  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>

.github/workflows/docs.yml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Cache choosenim
         id: cache-choosenim

.github/workflows/tests.yml

@@ -28,7 +28,7 @@ jobs:
 
 
     steps:
-      - uses: actions/checkout@v1
+      - uses: actions/checkout@v4
       - uses: iffy/install-nim@v4
         with:
           version: ${{ matrix.nimversion }}
@@ -44,7 +44,7 @@ jobs:
   Docs:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Docs
         run: docker-compose run docs