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

@@ -15,7 +15,7 @@ jobs:
     runs-on: ubuntu-22.04
 
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
     - name: Install Apt Dependencies
       run: sudo apt update && sudo apt install ninja-build qt6-base-dev libglx-dev libgl1-mesa-dev qt6-tools-dev qt6-tools-dev-tools qt6-l10n-tools libboost-dev libboost-date-time-dev libboost-iostreams-dev nlohmann-json3-dev libasound2-dev librtmidi-dev libpugixml-dev libminizip-dev doctest-dev
     - name: Create Build Directory
@@ -34,7 +34,7 @@ jobs:
     runs-on: macos-13
 
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
 
     - name: Version number
       id: version
@@ -90,7 +90,7 @@ jobs:
     runs-on: windows-2022
 
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
 
     - name: Version number
       id: version

.github/workflows/snap.yml

@@ -16,7 +16,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
       with:
         ref:  ${{ github.event.inputs.branch }}