v4.0.0

• #141 - breaking - recognize core OTEL_OTLP_EXPORTER_* variables (@AlbertoMonteiro)
• #145 - add GitHub issue templates (@nblumhardt)
• #146 - breaking - recognize OTEL_SERVICE_NAME (@nblumhardt)
• #147 - breaking - map events carrying SpanStartTimestamp as OTLP spans (@nblumhardt)
• #149 - README updates (@nblumhardt)

Breaking changes

• Sink behavior may change in the presence of OTEL_* environment variables. To prevent this, pass ignoreEnvironment: true to any of the WriteTo configuration methods.
• Log events carrying a SpanStartTimestamp property of type DateTime will now be recognized as spans rather than logs.