Install stringer for the linter tests

.github/workflows/test.yml

@@ -128,6 +128,7 @@ jobs:
         go install github.com/securego/gosec/v2/cmd/gosec@latest
         go install golang.org/x/tools/go/analysis/passes/shadow/cmd/shadow@latest
         go install honnef.co/go/tools/cmd/staticcheck@latest
+        go install golang.org/x/tools/cmd/stringer@latest
     - name: 'go install necessary tools (ubuntu)'
       if: always() && matrix.os == 'ubuntu-latest'
       run: |