Add workflow

Author: ChappIO

.github/workflows/build.yml

@@ -0,0 +1,18 @@
+on:
+  pull_request:
+  push:
+    branches:
+      - main
+  release:
+    types:
+      - created
+
+jobs:
+  build:
+    runs-on: ubuntu-20.04
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-go@v2
+        with:
+          go-version: '^1.17.8'
+      - run: go build ./cmd/git-backup