Udate moment version to 2.19.3 or newer

[peterblazejewicz]

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[x] bug report => Search github for a similar issue or PR before submitting
[ ] feature request => Please check if request is not on the roadmap already https://github.com/primefaces/primeng/wiki/Roadmap
[ ] support request => Please do not submit support request here, instead see http://forum.primefaces.org/viewforum.php?f=35

The moment (Moment.js) library used in project needs simple update to the next version with security vulnerability patched
https://nodesecurity.io/advisories?search=moment&version=2.18.1

Current behavior
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Expected behavior
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Minimal reproduction of the problem with instructions

git clone  https://github.com/primefaces/primeng.git
cd primeng
npm install

WARN notice [SECURITY] moment has the following vulnerability: 1 low. Go here for more details: https://nodesecurity.io/advisories?search=moment&version=2.18.1 - Run npm i npm@latest -g to upgrade your npm version, and then npm audit to get more info.

What is the motivation / use case for changing the behavior?
Update moment version to the recommended version

Please tell us about your environment:
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• Angular version: 5.X
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• PrimeNG version: 5.X
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  development: 6.0.0-SNAPSHOT

• 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 ]
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• Language: [all | TypeScript X.X | ES6/7 | ES5]
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• Node (for AoT issues): node --version =
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