v0.19.0

Many thanks to @lo1tuma, @Saeris, @sillvva, @kazizi55, @FleetAdmiralJakob, @kurtextrem, @xinha-sh and @husseyexplores for contributing to this release.

• Add notBytes, notLength, notSize and notValue validation function (pull request #194)
• Add support for unions as key of record and recordAsync schema (issue #201)
• Add support for pipeline validation to transform and transformAsync (issue #197)
• Change regex of email validation to improve performance and security (pull request #180)
• Change object and objectAsync schema to exclude non-existing keys (issue #199)
• Fix types at brand, transform and unwrap method (issue #195)
• Deprecate equal validation function in favor of value (issue #192)