build(deps): bump actions/checkout from 5 to 6

Bumps [actions/checkout](https://github.com/actions/checkout) from 5 to 6.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v5...v6)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/build.yml

@@ -14,7 +14,7 @@ jobs:
 
     steps:
       - name: Checkout pebble-firmware
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           repository: pebble-dev/pebble-firmware
           ref: main
@@ -53,7 +53,7 @@ jobs:
 
     steps:
       - name: Checkout pebble-android-sdk
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           repository: pebble-dev/pebble-android-sdk
 
@@ -74,7 +74,7 @@ jobs:
 
     steps:
       - name: Checkout pebble-ios-sdk
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           repository: pebble/pebble-ios-sdk
 
@@ -93,7 +93,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Download docs artifacts
         uses: actions/download-artifact@v6

.github/workflows/gitlint.yaml

@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-24.04
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           ref: ${{ github.event.pull_request.head.sha }}
           fetch-depth: 0

.github/workflows/test.yml

@@ -10,7 +10,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Setup Ruby
         uses: ruby/setup-ruby@v1