ci: bump actions/checkout from 6.0.3 to 7.0.0

Bumps [actions/checkout](https://github.com/actions/checkout) from 6.0.3 to 7.0.0.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@df4cb1c...9c091bb)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: 7.0.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/ci.yml

@@ -37,7 +37,7 @@ jobs:
   macos:
     runs-on: macos-latest
     steps:
-      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
       # Prebuilt cargo-generate (fast, deterministic — no compile). SHA-pinned;
       # Dependabot (github-actions) keeps it current.
       - uses: taiki-e/install-action@7a79fe8c3a13344501c80d99cae481c1c9085912 # v2.81.10
@@ -72,7 +72,7 @@ jobs:
   linux:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
       # System libraries GPUI needs on Linux (X11 + Wayland + Vulkan + fonts), plus
       # GTK/appindicator for the optional tray feature.
       - name: Install system dependencies
@@ -116,7 +116,7 @@ jobs:
   cargo-deny:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
+      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
       - uses: taiki-e/install-action@7a79fe8c3a13344501c80d99cae481c1c9085912 # v2.81.10
         with:
           tool: cargo-generate,cargo-deny