Update shadow-selection-polyfill

[web-padawan]

There is a new version released today: GoogleChromeLabs/shadow-selection-polyfill@ef88609

I will update my vaadin-quill branch to use this version and test how it works for us.

Potentially related issues: #49 #98 and maybe also #75 (need to verify).

[web-padawan]

Tried to upgrade and got the following error:

[Error] TypeError: Argument 1 ('node') to Selection.containsNode must be an instance of Node
	containsNode
	getRange
	getNativeRange
	getRange
	update
	Selection
	Quill
	ready
	_enableProperties
	connectedCallback
	connectedCallback
	connectedCallback
	(anonymous function)
	appendChild
	insertBefore
	createFrom
	(anonymous function)
	forEach
	forElements
	create
	(anonymous function)
	callFn (mocha.js:1168:147)
	(anonymous function) (mocha.js:1168)
	next (mocha.js:1274:1388)
	(anonymous function) (mocha.js:1276:122)
	timeslice (mocha.js:17:244)

The error is only thrown when ShadyDOM is in use.

[web-padawan]

Done by #145. We do not apply polyfill in ShadyDOM now so the above error should not happen.