add tests for various actions

example/.github/main.workflow

@@ -1,21 +0,0 @@
-workflow "build-and-deploy" {
-  on = "push"
-  resolves = ["deploy"]
-}
-
-action "build" {
-  uses = "./action1"
-  args = "echo 'build'"
-}
-
-action "test" {
-  uses = "docker://ubuntu:18.04"
-  args = "echo 'test'"
-  needs = ["build"]
-}
-
-action "deploy" {
-  uses = "./action2"
-  runs = ["/bin/sh", "-c", "cat $GITHUB_EVENT_PATH"]
-  needs = ["test"]
-}