Add cache step.

.github/workflows/go.yml

@@ -15,14 +15,24 @@ jobs:
         go:
         - '1.22'
     steps:
-    - uses: actions/checkout@v4
+    - name: Checkout the repo
+      uses: actions/checkout@v4
 
     - name: Set up Go
       uses: actions/setup-go@v5
       with:
         go-version: '${{ matrix.go }}'
         check-latest: true
 
+    - name: Cache modules
+      uses: actions/cache@v4
+      with:
+        path: |
+          ~/go/pkg
+        key: ${{ runner.os }}-go-${{ hashFiles('**/go.mod', '**/go.sum') }}
+        restore-keys: |
+          ${{ runner.os }}-go-
+
     - name: Build
       run: go build -v ./...