go.dev: clean up deployment

Delete separate learn service files, since the service has been deleted.
(learn.go.dev is now served by the same service as go.dev.)

Also make the yaml commands a bit more readable.

Change-Id: I8c453cb38bef84eb1d795e949c9bc315360c0deb
Reviewed-on: https://go-review.googlesource.com/c/website/+/323896
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Jamal Carvalho <jamal@golang.org>
diff --git a/go.dev/.firebaserc b/go.dev/.firebaserc
deleted file mode 100644
index 663d35d..0000000
--- a/go.dev/.firebaserc
+++ /dev/null
@@ -1,6 +0,0 @@
-{
-  "projects": {
-    "staging": "go-dev-staging",
-    "prod": "go-dev-prod"
-  }
-}
diff --git a/go.dev/app.learn.yaml b/go.dev/app.learn.yaml
deleted file mode 100644
index 467eb45..0000000
--- a/go.dev/app.learn.yaml
+++ /dev/null
@@ -1,8 +0,0 @@
-runtime: go115
-service: learn-go-dev
-main: ./cmd/frontend
-
-handlers:
-  - url: /.*
-    secure: always
-    script: auto
diff --git a/go.dev/app.staging.learn.yaml b/go.dev/app.staging.learn.yaml
deleted file mode 100644
index 6484cc2..0000000
--- a/go.dev/app.staging.learn.yaml
+++ /dev/null
@@ -1,8 +0,0 @@
-runtime: go115
-service: staging-learn-go-dev
-main: ./cmd/frontend
-
-handlers:
-  - url: /.*
-    secure: always
-    script: auto
diff --git a/go.dev/app.staging.yaml b/go.dev/app.staging.yaml
index 261d9e9..65c2d31 100644
--- a/go.dev/app.staging.yaml
+++ b/go.dev/app.staging.yaml
@@ -1,3 +1,6 @@
+# This app is deployed via Cloud Build as directed by cloudbuild.staging.yaml.
+# Do not deploy directly.
+
 runtime: go115
 service: staging-go-dev
 main: ./cmd/frontend
diff --git a/go.dev/app.yaml b/go.dev/app.yaml
index eb67097..b9e5b4f 100644
--- a/go.dev/app.yaml
+++ b/go.dev/app.yaml
@@ -1,6 +1,9 @@
+# This app is deployed via Cloud Build as directed by cloudbuild.yaml.
+# Do not deploy directly.
+
 runtime: go115
 service: go-dev
-main: ./cmd/frontend
+main: ./go.dev/cmd/frontend
 
 handlers:
   - url: /.*
diff --git a/go.dev/cloudbuild.yaml b/go.dev/cloudbuild.yaml
index 2d92918..080164e 100644
--- a/go.dev/cloudbuild.yaml
+++ b/go.dev/cloudbuild.yaml
@@ -12,8 +12,7 @@
     dir: go.dev
   - name: "gcr.io/cloud-builders/gcloud"
     entrypoint: bash
-    args: ["../go-app-deploy.sh", "app.yaml"]
-    dir: go.dev
+    args: ["./go-app-deploy.sh", "go.dev/app.yaml"]
   - name: 'mirror.gcr.io/library/golang'
     args: [
       "go", "run", "./cmd/versionprune", "--dry_run=false",