fix: reduce number of concurrent git processes spawned

[t1m0thyj]

Pre-flight checklist

• I have read the Contributing Guidelines on pull requests.
• If this is a code change: I have written unit tests and/or added dogfooding pages to fully verify the new behavior.
• If this is a new API or substantial change: the PR has an accompanying issue (closes #0000) and the maintainers have approved on my working plan.

Motivation

Fixes #10348 by adding an environment variable DOCUSAURUS_GIT_CONCURRENCY which defaults to 100.

Test Plan

I ran yarn clear:website && yarn build:website --locale en and the before/after time were the same.

Test links

Deploy preview: https://deploy-preview-_____--docusaurus-2.netlify.app/

Related issues/PRs

[facebook-github-bot]

Hi @t1m0thyj!

Thank you for your pull request and welcome to our community.

Action Required

In order to merge any pull request (code, docs, etc.), we require contributors to sign our Contributor License Agreement, and we don't seem to have one on file for you.

Process

In order for us to review and merge your suggested changes, please sign at https://code.facebook.com/cla. If you are contributing on behalf of someone else (eg your employer), the individual CLA may not be sufficient and your employer may need to sign the corporate CLA.

Once the CLA is signed, our tooling will perform checks and validations. Afterwards, the pull request will be tagged with CLA signed. The tagging process may take up to 1 hour after signing. Please give it that time before contacting us about it.

If you have received this in error or have any questions, please contact us at [email protected]. Thanks!

[github-actions]

⚡️ Lighthouse report for the deploy preview of this PR

URL	Performance	Accessibility	Best Practices	SEO	Report
/	🟢 91	🟢 98	🟢 96	🟢 100	Report
/docs/installation	🟠 60	🟢 97	🟢 100	🟢 100	Report
/docs/category/getting-started	🟠 75	🟢 100	🟢 100	🟠 86	Report
/blog	🟠 69	🟢 96	🟢 100	🟠 86	Report
/blog/preparing-your-site-for-docusaurus-v3	🔴 48	🟢 92	🟢 100	🟢 100	Report
/blog/tags/release	🟠 69	🟢 96	🟢 100	🟠 86	Report
/blog/tags	🟠 75	🟢 100	🟢 100	🟠 86	Report

[OzakIOne]

@t1m0thyj you have to sign the CLA otherwise we can't merge your PR, if you don't want I can make the PR myself

[t1m0thyj]

@t1m0thyj you have to sign the CLA otherwise we can't merge your PR, if you don't want I can make the PR myself

@OzakIOne Sorry I don't think I'm able to sign the CLA, so please feel free to make the PR on my behalf 🙂