Unable to build locally on mac

Following steps for local development here - https://github.com/conwnet/github1s#local-development
`yarn` went fine
`yarn watch` is failing

``` jai@mac github1s % yarn watch
yarn run v1.22.10
$ rm -rf dist && run-p watch:*
$ ./scripts/watch.sh
$ cd lib/vscode && yarn watch
$ cd extensions/github1s && yarn dev
$ cd scripts/watch && node watch-src.js
$ cd scripts/watch && node watch-dist.js
copy resources done!
rsync: link_stat "/Users/jai/gitlab1s/github1s/lib/vscode/node_modules/vscode-textmate" failed: No such file or directory (2)
rsync error: some files could not be transferred (code 23) at /AppleInternal/BuildRoot/Library/Caches/com.apple.xbs/Sources/rsync/rsync-55/rsync/main.c(996) [sender=2.6.9]
error Command failed with exit code 23.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
ERROR: "watch:setup" exited with 23.
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
```

OS: macOS 11.2 Big Sur

Any ideas what i might be missing ?

EDIT#1:
Tried using dev containers getting this errror for `yarn watch`
```node ➜ /workspaces/github1s (master) $ yarn watch
yarn run v1.22.5
$ rm -rf dist && run-p watch:*
$ cd lib/vscode && yarn watch
$ cd scripts/watch && node watch-src.js
$ cd extensions/github1s && yarn dev
$ ./scripts/watch.sh
$ cd scripts/watch && node watch-dist.js
copy resources done!
warning github1s@0.0.0: The engine "vscode" appears to be invalid.
$ webpack --config extension.webpack.config.js --watch
copy necessary node_modules done!
compile vscode builtin extensions...
(node:4953) UnhandledPromiseRejectionWarning: Error: Command failed: rsync -a /workspaces/github1s/lib/vscode/out/ /workspaces/github1s/dist/static/vscode
rsync: change_dir "/workspaces/github1s/lib/vscode/out" failed: No such file or directory (2)
rsync error: some files/attrs were not transferred (see previous errors) (code 23) at main.c(1207) [sender=3.1.3]

at ChildProcess.exithandler (child_process.js:308:12)
at ChildProcess.emit (events.js:314:20)
at maybeClose (internal/child_process.js:1022:16)
at Process.ChildProcess._handle.onexit (internal/child_process.js:287:5)
(node:4953) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 1)
(node:4953) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.
```

Start with the documented local-development steps and run `yarn watch`, then inspect `scripts/watch.sh`, `scripts/watch/watch-src.js`, and `scripts/watch/watch-dist.js` alongside the `lib/vscode` and `extensions/github1s` watch commands. Reproduce the reported macOS and container failures and trace the missing `vscode-textmate` or `lib/vscode/out` paths; done means the local watch build completes without these rsync errors.

Written by the indexing model from the issue text.