Merge pull request #29 from digitalocean/awg/ci

Add basic CI checks using GH actions

.github/golint/Dockerfile

@@ -0,0 +1,2 @@
+FROM golang:1.12.6
+RUN go get golang.org/x/lint/golint

.github/main.workflow

@@ -0,0 +1,34 @@
+workflow "Pull Request" {
+  # TODO(awg): This won't run checks on PRs from forks. For now that seems to be
+  # a limitation of GH actions.
+  on = "push"
+  resolves = [
+    "vet",
+    "lint",
+    "test",
+  ]
+}
+
+action "vet" {
+  uses = "docker://golang:1.12.6"
+  env = {
+    GOFLAGS = "-mod=vendor"
+  }
+  runs = ["go", "vet", "./..."]
+}
+
+action "lint" {
+  uses = "./.github/golint"
+  env = {
+    GOFLAGS = "-mod=vendor"
+  }
+  runs = ["sh", "-c", "golint -set_exit_status $(go list ./...)"]
+}
+
+action "test" {
+  uses = "docker://golang:1.12.6"
+  env = {
+    GOFLAGS = "-mod=vendor"
+  }
+  runs = ["go", "test", "-race", "-cover", "./..."]
+}