chore(deps): update actions/setup-go action to v6

Author: renovate[bot]

.github/workflows/oats-tests.yml

@@ -31,7 +31,7 @@ jobs:
           cache-read-only: ${{ github.event_name == 'pull_request' }}
 
       - name: Set up Go
-        uses: actions/setup-go@d35c59abb061a4a6fb18e82ac0862c26744d6ab5 # v5.5.0
+        uses: actions/setup-go@44694675825211faa026b3c33043df3e48a5fa00 # v6.0.0
         with:
           go-version: '1.25'