Typos in Tree.d.ts

[arotnov]

I'm submitting a ... (check one with "x")

[x] bug report
[ ] feature request
[ ] support request => Please do not submit support request here, instead see https://forum.primefaces.org/viewforum.php?f=57

Plunkr Case (Bug Reports)
Not needed

Current behavior
Methods onSelectionChange, nodeTemplate and onContextMenuSelectionChange in interface TreeProps is required.

Expected behavior
Methods onSelectionChange, nodeTemplate and onContextMenuSelectionChange in interface TreeProps (Tree.d.ts) must be optional (like others).

Minimal reproduction of the problem with instructions
Not needed

Please tell us about your environment:
No matter

• React version:
  16.5.1

• PrimeReact version:
  2.0.0-beta.7

• Browser: [all | Chrome XX | Firefox XX | IE XX | Safari XX | Mobile Chrome XX | Android X.X Web Browser | iOS XX Safari | iOS XX UIWebView | iOS XX WKWebView ]
  Any

• Language: [all | TypeScript X.X | ES6/7 | ES5]
  Typescript 3.0.3