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] <support@github.com>

Author: dependabot[bot]

.github/workflows/ns_test.yml

@@ -7,7 +7,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
 
     - name: Set up java
       uses: actions/setup-java@v5

.github/workflows/prep_release.yml

@@ -12,7 +12,7 @@ jobs:
 
     steps:
     - name: Checkout code
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
 
     - name: Set up JDK 17
       uses: actions/setup-java@v5

.github/workflows/sbt_test.yml

@@ -19,7 +19,7 @@ jobs:
           - { ver: '21', run_nextflow: true, run_coverage: false, nxf_ver: latest-edge }
 
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
 
     - uses: viash-io/viash-actions/project/update-docker-engine@v6
       if: runner.os == 'Linux'

.github/workflows/weekly_branch_tests.yml

@@ -27,7 +27,7 @@ jobs:
 
     steps:
     - name: Checkout ${{ matrix.branch }} branch
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
       with:
         ref: ${{ matrix.branch }}