Pin linter version

Same as fortio/workflows#67
(need to figure cross org share actually rather than copy-pasta)

.github/workflows/gochecks.yml

@@ -27,6 +27,8 @@ jobs:
         run: curl -fsS -o .golangci.yml https://raw.githubusercontent.com/fortio/workflows/main/golangci.yml
       - name: Run golangci-lint
         uses: golangci/golangci-lint-action@aaa42aa0628b4ae2578232a66b541047968fac86 # pin@v6
+        with:
+          version: 1.60.3
       - name: Run tests
         run: |
           go version