Fix h3IsValid false positives on certain invalid strings, bump core library to 3.6.3

[nrabinowitz]

Fixes #79

This diff has an appreciable impact on h3IsValid benchmarks:

master

h3IsValid x 4,047,006 ops/sec ±1.14% (81 runs sampled)

this branch

h3IsValid x 3,314,650 ops/sec ±0.85% (87 runs sampled)

However I can't find a more performant approach that fixes the false positives, which stem from parseInt ignoring unparsable chars. Open to suggestions. The perf is still very good, obviously, but this could be an issue if consumers need to validate large sets of hexagons.

[coveralls]

Pull Request Test Coverage Report for Build 174

• 2 of 2 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 100.0%

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Totals
Change from base Build 170:	0.0%
Covered Lines:	363
Relevant Lines:	363

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💛 - Coveralls

[isaacbrodsky]

nit: do we want to mention what was changed in the core library?

[dfellis]

I say unless we come up with a good way to auto-populate that, it's a bunch of make-work and not super valuable (those interested can look at the core library CHANGELOG).

[nrabinowitz]

Added a short note. I think it's worthwhile if the changes are substantive, since most consumers will only look at the binding notes and may not realize they need to look further to understand changes.