build: add a simple github build action

A build job is now configured on pr and push event which runs build and unit
tests on all the Go source files.

.github/workflows/build.yaml

@@ -0,0 +1,26 @@
+name: build
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - main
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Set up Go
+        uses: actions/setup-go@v2
+        with:
+          go-version: 1.19
+
+      - name: Build
+        run: go build -v ./...
+
+      - name: Test
+        run: go test -v ./...

go.mod

@@ -1,6 +1,6 @@
 module github.com/ebay/releaser
 
-go 1.17
+go 1.19
 
 require (
 	github.com/Masterminds/sprig/v3 v3.2.3