Update local_converter.cr

Create iso8601_converter.cr

Create time_converter.cr

Adds time converter for parsing time strings

Update ext.cr (#13)

Adds missing require for epochtime converter module

Set shard version 0.2.3

includes required predicate

Support Crystal v1.0.0

Merge pull request #8 from eliasjpr/refactor

[v0.2.0] Refactor and API Changes

Fixes validate! method