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

@@ -26,7 +26,7 @@ jobs:
         rust: [stable]
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Install ${{ matrix.rust }}
         uses: actions-rs/toolchain@v1
         with:
@@ -46,7 +46,7 @@ jobs:
           ["openssl_tls,k8", "openssl_tls", "native_tls,k8", "native_tls"]
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Install ${{ matrix.rust }}
         uses: actions-rs/toolchain@v1
         with:
@@ -63,7 +63,7 @@ jobs:
         os: [ubuntu-latest]
         rust: [stable]
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Install ${{ matrix.rust }}
         uses: actions-rs/toolchain@v1
         with:
@@ -80,7 +80,7 @@ jobs:
         os: [ubuntu-latest]
         rust: [stable]
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Install ${{ matrix.rust }}
         uses: actions-rs/toolchain@v1
         with:
@@ -102,7 +102,7 @@ jobs:
         rust: [stable]
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Install ${{ matrix.rust }}
         uses: actions-rs/toolchain@v1
         with: