add go-apidiff action (#151)

Signed-off-by: Joe Lanford <joe.lanford@gmail.com>

.github/workflows/go-apidiff.yaml

@@ -0,0 +1,20 @@
+name: go-apidiff
+
+on:
+  pull_request:
+
+jobs:
+  go-apidiff:
+    runs-on: ubuntu-latest
+    steps:
+    - name: Check out code into the Go module directory
+      uses: actions/checkout@v3
+      with:
+        fetch-depth: 0
+    - name: Set up Go
+      uses: actions/setup-go@v4
+      with:
+        go-version-file: "go.mod"
+      id: go
+    - name: Run go-apidiff
+      uses: joelanford/go-apidiff@main