Release v0.2.0

Update in this release:

• follow latest test format from otelmux
• show how to set service name on tracer provider from example
• remove set HTTPResponseContentLengthKey since it is better to be set by end user themselves
• remove set HTTPTargetKey since it has been set automatically in HTTPServerAttributesFromHTTPRequest
• simplify dependencies in go.mod

Updated dependencies:

• otel => v1.0.1
• go-chi/chi => v5.0.4