build error while excuting yarn build:vscode on riscv

[ShenChongwu]

root@lpi4a:/home/sipeed/bench/node/code-server# yarn build
yarn run v1.22.22
$ ./ci/build/build-code-server.sh
Done in 143.56s.
root@lpi4a:/home/sipeed/bench/node/code-server# export VERSION='0.0.1' && yarn build:vscode
yarn run v1.22.22
$ ./ci/build/build-vscode.sh
error: pathspec 'product.json' did not match any file(s) known to git
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

[code-asher]

Ah you might have missed the install and submodule steps. We list them under the development section but not the build section. We should probably list them in both sections.

code-server/docs/CONTRIBUTING.md

Lines 90 to 93 in ab4b36f

	1. `git clone https://github.com/coder/code-server.git` - Clone `code-server`
	2. `git submodule update --init` - Clone `vscode` submodule
	3. `quilt push -a` - Apply patches to the `vscode` submodule.
	4. `yarn` - Install dependencies