build(deps): bump actions/checkout from 3.5.3 to 4.0.0

Bumps [actions/checkout](https://github.com/actions/checkout) from 3.5.3 to 4.0.0.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v3.5.3...v4.0.0)

---
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/book.yml

@@ -12,7 +12,7 @@ jobs:
       contents: write
     steps:
       - name: Checkout
-        uses: actions/checkout@v3.5.3
+        uses: actions/checkout@v4.0.0
 
       - name: Setup mdBook
         uses: peaceiris/actions-mdbook@v1.2.0

.github/workflows/main.yml

@@ -25,7 +25,7 @@ jobs:
         override: true
         components: rustfmt, clippy
 
-    - uses: actions/checkout@v3.5.3
+    - uses: actions/checkout@v4.0.0
 
     - name: Format
       uses: actions-rs/cargo@v1.0.3
@@ -99,7 +99,7 @@ jobs:
         launchctl unload -w ${SL}/LaunchAgents/${PL}.plist
         sudo launchctl unload -w ${SL}/LaunchDaemons/${PL}.Root.plist
 
-    - uses: actions/checkout@v3.5.3
+    - uses: actions/checkout@v4.0.0
 
     - uses: actions-rs/toolchain@v1.0.7
       id: toolchain
@@ -123,7 +123,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v3.5.3
+    - uses: actions/checkout@v4.0.0
 
     - uses: actions-rs/toolchain@v1.0.7
       id: toolchain
@@ -146,9 +146,9 @@ jobs:
         repo: ["aws/s2n-quic"]
 
     steps:
-    - uses: actions/checkout@v3.5.3
+    - uses: actions/checkout@v4.0.0
 
-    - uses: actions/checkout@v3.5.3
+    - uses: actions/checkout@v4.0.0
       with:
         repository: ${{ matrix.repo }}
         path: "target/integration/${{ matrix.repo }}"