added workflow

I'm trying out GitHub Actions. Let's see how it goes.

.github/workflows/go.yml

@@ -0,0 +1,34 @@
+name: Go
+on:
+  push:
+    branches:
+      - master
+  pull-request:
+    branches:
+      - master
+jobs:
+
+  build:
+    name: Build
+    runs-on: ubuntu-latest
+    steps:
+
+    - name: Set up Go 1.12
+      uses: actions/setup-go@v1
+      with:
+        go-version: 1.12
+      id: go
+
+    - name: Check out code into the Go module directory
+      uses: actions/checkout@v1
+
+    - name: Get dependencies
+      run: |
+        go get -v -t -d ./...
+        if [ -f Gopkg.toml ]; then
+            curl https://raw.githubusercontent.com/golang/dep/master/install.sh | sh
+            dep ensure
+        fi
+
+    - name: Build
+      run: go build -v .