Search input renderer for Blueprints.js broke

[dlech]

Typing to trigger the search crashes at runtime with:

Uncaught TypeError: el.focus is not a function
    at ref (SearchInput.js:72:1)
    at commitAttachRef (react-dom.development.js:20023:1)
    at commitLayoutEffects (react-dom.development.js:22808:1)
    at HTMLUnknownElement.callCallback (react-dom.development.js:188:1)
    at Object.invokeGuardedCallbackDev (react-dom.development.js:237:1)
    at invokeGuardedCallback (react-dom.development.js:292:1)
    at commitRootImpl (react-dom.development.js:22541:1)
    at unstable_runWithPriority (scheduler.development.js:653:1)
    at runWithPriority$1 (react-dom.development.js:11039:1)
    at commitRoot (react-dom.development.js:22381:1)

So I suppose this could just be a bug and may not be a React version compatibility issue.

Originally posted by @dlech in #196 (comment)

[dlech]

This happens because the SearchInput rendered now provides a ref property in inputProps. This is passed to the Blueprints.js InputGroup component. However, the ref property of the InputGroup component is for the React component, not the underlying HTML element. Since the InputGroup component doesn't have a focus method, it triggers the crash.

[lukasbach]

Thanks a lot for your contribution! The fix is deployed as of 2.0.1.