Upgrade to Babel 7

[ankurkaushal]

Reasons for making this change

Using my work account (@ankurkaushal360), I opened an issue here, #1319 mentioning babel upgrade & I was told to it would be a good idea.

So this pull upgrades the Babel 6 to Babel 7 using npx babel-upgrade --write and does the following things:

• Removes deprecated babel-plugin-react-transform with @babel/plugin-transform-react-jsx
• Updates a few files with default exports as they were throwing warnings while running dev like this:

As far as I can tell, everything should work as it is. Even all the tests are passing too. I don't think I need to add / update any tests for this change.

Also, I haven't updated the package.json version yet. Though I think I need to update it. Would you prefer major or minor version bump?

Checklist

• I'm updating documentation
  • I've checked the rendering of the Markdown text I've added
• I'm adding or updating code
  • I've added and/or updated tests
  • I've updated docs if needed
  • I've run npm run cs-format on my branch to conform my code to prettier coding style
• I'm adding a new feature
  • I've updated the playground with an example use of the feature

[epicfaace]

Looks good, thanks for making this change! Can you mark this pull request as "ready for review" if you're done?

You don't need to add a version bump; usually @glasserc does that when releasing a new version with the latest pull requests. I would think this would only be a patch version bump because it is just updating development tools, not the actual functionality of the library itself.

[ankurkaushal]

@epicfaace Marked this PR as 'ready for review' :)

[epicfaace]

Thanks!