Update actions/setup-go action to v6 (#53)

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

Author: renovate[bot]

.github/workflows/ci.yml

@@ -43,7 +43,7 @@ jobs:
         uses: actions/checkout@v5
 
       - name: Setup Go
-        uses: actions/setup-go@v5
+        uses: actions/setup-go@v6
         with:
           go-version: ${{ env.GO_VERSION }}
           cache: false  # The golangci-lint action does its own caching.
@@ -63,7 +63,7 @@ jobs:
         uses: actions/checkout@v5
 
       - name: Setup Go
-        uses: actions/setup-go@v5
+        uses: actions/setup-go@v6
         with:
           go-version: ${{ env.GO_VERSION }}