Bump actions/checkout from 4.1.7 to 4.2.1

Bumps [actions/checkout](https://github.com/actions/checkout) from 4.1.7 to 4.2.1.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@692973e...eef6144)

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

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

.github/workflows/main.yml

@@ -31,7 +31,7 @@ jobs:
       GIT_CLONE_PROTECTION_ACTIVE: false
     steps:
       - name: checkout
-        uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4.1.7
+        uses: actions/checkout@eef61447b9ff4aafe5dcd4e0bbf5d482be7e7871 # v4.2.1
         with:
           submodules: recursive
       # Assumes clang/cmake/libc++/libc++abi are installed on GitHub Actions Runner
@@ -93,7 +93,7 @@ jobs:
     timeout-minutes: 30
     steps:
       - name: checkout
-        uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4.1.7
+        uses: actions/checkout@eef61447b9ff4aafe5dcd4e0bbf5d482be7e7871 # v4.2.1
         with:
           submodules: recursive
       - name: checkout ffmpeg
@@ -139,7 +139,7 @@ jobs:
     timeout-minutes: 30
     steps:
       - name: checkout
-        uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4.1.7
+        uses: actions/checkout@eef61447b9ff4aafe5dcd4e0bbf5d482be7e7871 # v4.2.1
         with:
           fetch-depth: 0
           submodules: recursive
@@ -183,7 +183,7 @@ jobs:
         working-directory: ${{ env.NANOEM_RUST_DIRECTORY }}
     steps:
       - name: checkout
-        uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4.1.7
+        uses: actions/checkout@eef61447b9ff4aafe5dcd4e0bbf5d482be7e7871 # v4.2.1
       - name: setup cargo-deny
         uses: EmbarkStudios/cargo-deny-action@8371184bd11e21dcf8ac82ebf8c9c9f74ebf7268 # v2.0.1
         with:
@@ -229,7 +229,7 @@ jobs:
       CXX: clang++
     steps:
       - name: checkout
-        uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4.1.7
+        uses: actions/checkout@eef61447b9ff4aafe5dcd4e0bbf5d482be7e7871 # v4.2.1
         with:
           submodules: recursive
       - name: initialize CodeQL