build(deps): bump actions/setup-go from 5 to 6

Bumps [actions/setup-go](https://github.com/actions/setup-go) from 5 to 6.
- [Release notes](https://github.com/actions/setup-go/releases)
- [Commits](actions/setup-go@v5...v6)

---
updated-dependencies:
- dependency-name: actions/setup-go
  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/tests.yml

@@ -68,7 +68,7 @@ jobs:
     - name: Install test dependencies
       run: sudo apt-get install -y libgpgme-dev libbtrfs-dev
     - uses: actions/checkout@v5
-    - uses: actions/setup-go@v5
+    - uses: actions/setup-go@v6
       with:
         go-version: "1.23"
     - env:
@@ -105,7 +105,7 @@ jobs:
     runs-on: ubuntu-22.04
     steps:
       - name: Set up Go 1.23
-        uses: actions/setup-go@v5
+        uses: actions/setup-go@v6
         with:
           go-version: "1.23"
         id: go
@@ -153,7 +153,7 @@ jobs:
     steps:
 
       - name: Set up Go 1.23
-        uses: actions/setup-go@v5
+        uses: actions/setup-go@v6
         with:
           go-version: "1.23"
         id: go