Updated codesandbox example (#1609)

* docs: push "hello world" codesandbox to stay up to date automatically

* docs: update CodeSandbox links

* fix: rename example directory

* docs: revert sandbox URL change on README

* refactor: rename playground directory to codesandbox

* chore: update CodeSandbox links

.github/ISSUE_TEMPLATE.md

@@ -24,7 +24,7 @@
 
 <!--
 Please try to re-create the issue using our CodeSandbox template available here:
-https://codesandbox.io/s/x2mjypo6pp
+https://codesandbox.io/s/github/IBM/carbon-components-react/tree/master/examples/codesandbox
 
 This helps reduce the issue to an isolated case that helps us out when debugging.
 If you're able to reproduce using the CodeSandbox link above, please include the

README.md

@@ -32,9 +32,9 @@ yarn add carbon-components-react carbon-components carbon-icons
 
 3. For older browsers (e.g. IE11), polyfills listed in [`carbon-components-react/.storybook/polyfills.js` file](./.storybook/polyfills.js) is required.
 
-If you just want to try out `carbon-components-react`, you can also use [CodeSandbox](https://codesandbox.io).
+If you just want to try out `carbon-components-react`, you can also use [CodeSandbox](https://codesandbox.io/s/github/IBM/carbon-components-react/tree/master/examples/codesandbox).
 
-[![Edit carbon-components-react](https://codesandbox.io/static/img/play-codesandbox.svg)](https://codesandbox.io/s/x2mjypo6pp)
+[![Edit carbon-components-react](https://codesandbox.io/static/img/play-codesandbox.svg)](https://codesandbox.io/s/github/IBM/carbon-components-react/tree/master/examples/codesandbox)
 
 ## Development