2.1.0

Switch to Apache license

Bumped:

• vert.x to 4.3.1
• kotlin to 1.7.0
• kotlin-coroutines to 1.6.2
• kotlinpoet to 1.12.0

Added:

• Support for one-way calls #36

Improvements:

• Logs are more useful now
• Annotation processor logs errors instead of logging + throwing them