Fixed - sans-serif font family not available in iOS

[ishansinghania]

What does this implement/fix? Explain your changes. sans-serif font family is not available in iOS, so app will crash.

Does this close any currently open issues? close #56

Screenshots If applicable, add screenshots of end result.

Any other comments?

Where has this been tested?

• Magento Version: [e.g. 2.1.0]
• Device: [e.g. iPhone6]
• OS: [e.g. iOS8.1]
• Version [e.g. 22]

[sanjeevyadavIT]

@all-contributors please add ishansinghania for bug

[allcontributors[bot]]

@alexakasanjeev

I've put up a pull request to add @ishansinghania! :tada: