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

| datasource  | package          | from | to |
| ----------- | ---------------- | ---- | -- |
| github-tags | actions/setup-go | v5   | v6 |


Signed-off-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/sync.yaml

@@ -31,7 +31,7 @@ jobs:
           sparse-checkout: api/v1
 
       - name: Setup Go
-        uses: actions/setup-go@v5
+        uses: actions/setup-go@v6
         with:
           go-version-file:  cloudnative-pg/go.mod