message: Fix contributing guide, renames master to main
diff: @@ -48,9 +48,9 @@ make your change to (and send a PR to) depends on the type of change you are mak
  Here is our branch breakdown:
  -- `master` - Make your change to the `master` branch if it is an *urgent* hotfix.
  +- `main` - Make your change to the `main` branch if it is an *urgent* hotfix.
  - `dev` - Make your change to `dev` if it is a *non-urgent* bugfix or a backwards-compatible feature.
  -- `next` - Make your change to `next` if it is a breaking change, or wild/crazy idea.
  +- `v4.x`, `v5.3.x`, `v5.2.x`, etc - Make your change to legacy branches to patch old releases if your fix *only* applies to older versions.
  Your change should be made directly to the branch in your fork, or to a branch in your fork made off of
  one of the above branches.
  