Allow gh-pages deployment to persist CNAME file

[austin-denoble]

Problem

We've been looking at adding custom domains to our documentation references which are hosted via GitHub pages. When applying a custom domain, GitHub modifies the source branch and commits a CNAME file automatically.

See here: https://github.com/pinecone-io/pinecone-ts-client/blob/gh-pages/CNAME

If you're deploying to this branch as a part of CI, you need to handle maintaining the CNAME file. We're currently using the git-publish-subdir-action to achieve this: https://github.com/marketplace/actions/push-git-subdirectory-as-branch. This action blows away everything unless you specify specific files to persist.

Solution

The action we're using supports passing a CLEAR_GLOBS_FILE argument allowing you to control what's replaced and what's persisted: https://github.com/marketplace/actions/push-git-subdirectory-as-branch#custom-clear-operations

• Add .clear-target-files under .github/. This file tells the action to clear everything but persist the CNAME file.
• Update merge.yml to pass the file to the action in the merge workflow -> docs deployment step.

Type of Change

• Infrastructure change (CI configs, etc)

Test Plan

Once this change is merged we can check the gh-pages branch to make sure the CNAME file is not blown away when we regenerate things and push to gh-pages.

[austin-denoble]

I figured putting this under .github since it's specifically CI related was fine.