[maven-release-plugin] copy for tag 9.0.0

Lower case headers in response and use TreeMap to allow case insensit…

…ive access (OpenFeign#418)

[maven-release-plugin] prepare for next development iteration

Update Bintray API key

Recognizes reason phrase is nullable and not set when using http/2

See httpwg/http2-spec#202
Fixes OpenFeign#382

Fixes dispatch for toString, equals, hashCode in hystrix

This copies missing logic from `FeignInvocationHandler` to
`HystrixInvocationHandler`, preventing NPEs when calling methods defined
on `java.lang.Object`.

Do not error on interfaces with default methods.

Pass calls to default methods on proxy through to implementation on interface.

Documents intent of client tests

Fixed version log

JAXRS: Fix NPE when @path is first on a method