ci: update actions/setup-go action to v6 (#70)

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

Author: renovate[bot]

.github/workflows/test.yaml

@@ -34,7 +34,7 @@ jobs:
       - uses: actions/checkout@v5
 
       - name: Install Go
-        uses: actions/setup-go@v5
+        uses: actions/setup-go@v6
         with:
           go-version: "${{ matrix.go_version }}"
           cache-dependency-path: "**/*.sum"