[maven-release-plugin] copy for tag 2.15.0

Fixes typo in travis config

[maven-release-plugin] copy for tag 2.14.2

[maven-release-plugin] copy for tag 2.14.1

[maven-release-plugin] copy for tag v2.14.0

[maven-release-plugin] copy for tag v2.13.0

[maven-release-plugin] copy for tag 2.12.9

Adds workaround for gzip compression regression (openzipkin#2497)

It is costly to ship uncompressed json to browsers. This puts in a
stop-gap.

Fixes openzipkin#2495

[maven-release-plugin] copy for tag 2.12.8

Updates to Spring Boot 2.1.4 (openzipkin#2490)