Bump actions/checkout from 3 to 4

Bumps [actions/checkout](https://github.com/actions/checkout) from 3 to 4.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v3...v4)

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

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

.github/workflows/ci.yml

@@ -5,7 +5,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: rustup
         uses: actions-rs/toolchain@v1
         with:
@@ -24,7 +24,7 @@ jobs:
     runs-on: ${{ matrix.platform }}
     steps:
       - name: checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: rustup
         uses: actions-rs/toolchain@v1
         with:
@@ -42,7 +42,7 @@ jobs:
     runs-on: ${{ matrix.platform }}
     steps:
       - name: checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: rustup
         uses: actions-rs/toolchain@v1
         with: