Bump actions/checkout from 6 to 6.0.3 (#62)

Bumps [actions/checkout](https://github.com/actions/checkout) from 6 to 6.0.3.
- [Release notes](https://github.com/actions/checkout/releases)
- [Commits](https://github.com/actions/checkout/compare/v6...v6.0.3)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: 6.0.3
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/ci.yml

@@ -19,7 +19,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v6
+        uses: actions/checkout@v6.0.3
 
       - name: Setup Rust
         uses: dtolnay/rust-toolchain@stable

.github/workflows/release.yml

@@ -26,7 +26,7 @@ jobs:
       tag: ${{ steps.meta.outputs.tag }}
       ref: ${{ steps.meta.outputs.ref }}
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v6.0.3
         with:
           ref: ${{ inputs.ref }}
           persist-credentials: false
@@ -100,7 +100,7 @@ jobs:
           APP_ID: ${{ vars.APP_ID }}
           APP_SLUG: ${{ steps.app-token.outputs.app-slug }}
 
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v6.0.3
         with:
           token: ${{ steps.app-token.outputs.token }}
           persist-credentials: false