fix(ci): use golangci-lint v2 for Go 1.25 compatibility

golangci-lint v1.64.8 was built with Go 1.24 and rejects
go.mod targeting Go 1.25. Pin to v2.8.0 via action v7.

Author: vnykmshr

.github/workflows/ci.yml

@@ -18,7 +18,7 @@ jobs:
           go-version-file: go.mod
       - run: make fmt-check
       - run: make vet
-      - uses: golangci/golangci-lint-action@v6
+      - uses: golangci/golangci-lint-action@v7
         with:
-          version: latest
+          version: v2.8.0
       - run: make test