v0.12.0

Added

• Instrumentation library support #402
• Batch observer support #429
• with_unit methods in metrics #431

Changed

• Dependencies updates #410
• Add Send, Sync to AsyncInstrument in metrics #422
• Add Send, Sync to InstrumentCore in metrics #423
• Replace regex with custom logic #411
• Update tokio to v1 #421

Removed

• Moved http dependencies into a new opentelemetry-http crate #415
• Remove tonic dependency #414