chore: improve GitHub Actions workflows

- Use go-version-file to read version from go.mod
- Enable Go module caching for faster builds (30-60s improvement)
- Fix release workflow to only run unit tests (skip acceptance tests that need Ginkgo)

Author: malston

.github/workflows/ci.yml

@@ -21,7 +21,8 @@ jobs:
     - name: Set up Go
       uses: actions/setup-go@v5
       with:
-        go-version: '1.25.1'
+        go-version-file: 'go.mod'
+        cache: true
 
     - name: Install Ginkgo CLI
       run: go install github.com/onsi/ginkgo/v2/ginkgo@latest
@@ -56,7 +57,8 @@ jobs:
     - name: Set up Go
       uses: actions/setup-go@v5
       with:
-        go-version: '1.25.1'
+        go-version-file: 'go.mod'
+        cache: true
 
     - name: Build binary
       run: |

.github/workflows/release.yml

@@ -22,12 +22,11 @@ jobs:
     - name: Set up Go
       uses: actions/setup-go@v5
       with:
-        go-version: '1.25.1'
+        go-version-file: 'go.mod'
+        cache: true
 
-    - name: Run tests
-      run: |
-        go test -v ./pkg/...
-        go test -v ./test/...
+    - name: Run unit tests
+      run: go test -v ./pkg/...
 
     - name: Build binaries
       env: