[gitpod] Run "make watch" in a second terminal (#11718)

Co-authored-by: Huáng Jùnliàng <jlhwung@gmail.com>

[skip ci]

.gitpod.yml

@@ -2,6 +2,24 @@
 tasks:
   - init: make bootstrap
     command: make watch
+  - openMode: split-right
+    command: |-
+      clear && echo '
+      Welcome to Gitpod!
+
+      If you haven'\''t forked Babel yet and you want to prepare a PR, you can use
+      the Ctrl+P (or ⌘P) shortcut, type `>Fork` and press ENTER: Gitpod\ will
+      create the fork for you.
+
+      <-- The other terminal is building Babel. It should automatically rebuild
+          when you change a file, so you don'\''t need to worry about it.
+          If it'\''s still building, please wait until it'\''s finished!
+
+      If you want to run the tests, you can run `yarn jest` in this terminal,
+      or filter by package name (for example, `yarn jest babel-parser`).
+      '
+
+#' # <-- This is just because the gitpod theme has broken syntax highlighting
 
 github:
   # https://www.gitpod.io/docs/prebuilds/#configure-prebuilds

Makefile

@@ -256,11 +256,12 @@ publish-eslint:
 bootstrap-only: lerna-bootstrap
 
 yarn-install: clean-all
-	yarn --ignore-engines
+	# Gitpod prebuilds have a slow network connection, so we need more time
+	yarn --ignore-engines --network-timeout 100000
 
 lerna-bootstrap: yarn-install
 # todo: remove `-- -- --ignore-engines` in Babel 8
-	$(YARN) lerna bootstrap -- -- --ignore-engines
+	$(YARN) lerna bootstrap -- -- --ignore-engines --network-timeout 100000
 
 bootstrap: bootstrap-only
 	$(MAKE) build