[Archive] Updated default branch from master -> main in tldr-node-client, added branch protection rule for the main branch

[kbdharun]

Changes

• Updated the default branch from master -> main as suggested in Transition from master to main branch tldr-node-client#400.
  • I have changed the base branch of currently open PRs to main.
  • Added CI (same workflow that we previously used here) for syncing master with main (as there might be some repackaged versions building from master).
• Branch protection rule preventing direct commit to main has been added (by default PRs should be created and it would need at least 1 approving review to be merged) [Force pushing is still allowed for all collaborators]