Bump actions/checkout from 5 to 6 in the all group

Bumps the all group with 1 update: [actions/checkout](https://github.com/actions/checkout).


Updates `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
  dependency-group: all
...

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

Author: dependabot[bot]

.github/workflows/test.yml

@@ -67,7 +67,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     steps:
       - name: Checkout Viper-IDE
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Install Node.js
         uses: actions/setup-node@v6
@@ -260,7 +260,7 @@ jobs:
     steps:
       # we have to checkout the repo to read client/package.json later on:
       - name: Checkout Viper-IDE
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Download packaged Viper IDE
         uses: actions/download-artifact@v6

.github/workflows/update-viperserver.yml

@@ -18,7 +18,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Check out the repo
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Update ViperServer version used by the tests
         run: |

.github/workflows/update-vscode.yml

@@ -18,7 +18,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Check out the repo
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Update VS Code version used by the tests
         run: |