Bump actions/checkout from 5 to 6 (#1156)

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](https://github.com/actions/checkout/compare/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] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/raspi.yml

@@ -38,7 +38,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Checkout
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
 
     - name: Create Build Environment
       run: |
@@ -57,16 +57,16 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Checkout
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
 
     - name: Checkout libmcp23s17 repo
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
       with:
         repository: piface/libmcp23s17
         path: ./apps/piface/libmcp23s17
 
     - name: Checkout libpifacedigital repo
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
       with:
         repository: piface/libpifacedigital
         path: ./apps/piface/libpifacedigital
@@ -106,10 +106,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Checkout
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
 
     - name: Checkout pigpio repo
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
       with:
         repository: joan2937/pigpio
         path: ./apps/blinkt/pigpio