ci: add Actions workflow

.github/main.workflow

@@ -0,0 +1,31 @@
+workflow "lint, test, deploy" {
+  on = "push"
+  resolves = [
+    "lint",
+    "test",
+    "deploy",
+  ]
+}
+
+action "install" {
+  uses = "actions/npm@master"
+  args = "install"
+}
+
+action "lint" {
+  needs = "install"
+  uses = "actions/npm@master"
+  args = "run lint"
+}
+
+action "test" {
+  needs = "install"
+  uses = "actions/npm@master"
+  args = "test"
+}
+
+action "deploy" {
+  needs = "install"
+  uses = "primer/deploy@master"
+  args = "test"
+}