message: fix(docs): update branch name
diff: @@ -33,8 +33,8 @@ minimise the chance of merge conflicts.
  ```sh
  git remote add upstream git@github.com:chakra-ui/chakra-ui.git
  -git checkout master
  -git pull upstream master
  +git checkout main
  +git pull upstream main
  git checkout -b my-feature-branch
  ```
  