chore: improve from

https://ashishb.net/tech/common-pitfalls-of-github-actions/
https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actions#concurrency

.github/workflows/go.yml

@@ -4,9 +4,21 @@ on:
   push:
     branches:
       - main
+    paths:
+      - "**.go"
+      - "go.mod"
+      - "go.sum"
   pull_request:
     branches:
       - main
+    paths:
+      - "**.go"
+      - "go.mod"
+      - "go.sum"
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
 
 jobs:
   test: