Update react reference to new UI components (#6374)

Author: ashika01

CONTRIBUTING.md

@@ -109,7 +109,7 @@ $ yarn build --scope @aws-amplify/auth
 
 ```
 $ yarn run test --scope @aws-amplify/auth
-$ yarn run test --scope aws-amplify-react
+$ yarn run test --scope @aws-amplify/ui-components
 ```
 
 > Note: There is a commit hook that will run the tests prior to committing. Please make sure if you are going to provide a pull request to be sure you include unit tests with your functionality and that all tests pass.
@@ -176,7 +176,7 @@ _[Skip step 1 to 3 if you have already done this]_
 2. Clone your fork locally: `git clone git@github.com:YOUR_GITHUB_USERNAME/amplify-js.git`
 3. Run `yarn && yarn bootstrap` in the repository root
 4. Within your fork, create a new branch based on the issue (e.g. Issue #123) you're addressing - `git checkout -b "group-token/short-token-[branch-name]"` or `git checkout -b "short-token/[branch-name]"`
-   - Use grouping tokens at the beginning of the branch names. \_For e.g, if you are working on changes specific to amplify-ui-components, then you could start the branch name as `ui-components/...`
+   - Use grouping tokens at the beginning of the branch names. \_For e.g, if you are working on changes specific to `amplify-ui-components`, then you could start the branch name as `ui-components/...`
    - short token
      - feat
      - chore