Replace PropTypes.func with PropTypes.elementType

[maddieeiddam]

Closes #633

[maddieeiddam]

@skllcrn @karaggeorge @sindresorhus Hmm - so I can see that the build is failing because it's seeing elementType as an invalid prop type...did I make an error, do I need to change something else, or is elementType just not supported yet?

[sindresorhus]

The build failure is because of jsx-eslint/eslint-plugin-react#2188. I've disabled the rule in master. Just rebase from master.

[ljharb]

That rule enumerates the actual prop-types library; did perhaps someone forget to update prop-types? I see this repo has a lockfile; that's a common bug when using one.

[sindresorhus]

Yes, it was the lockfile. I thought it was not as I had already tried to uninstall and then reinstall eslint-plugin-react, but it seemed I had to force regenerate the lockfile to make it work.

[sindresorhus]

Looks good to me.

@maddieeiddam Can you fix the merge conflict?

[karaggeorge]

LGTM

[sindresorhus]

Thanks, @maddieeiddam 🙌 Great contribution :)