New upstream version 1.28.0

.kokoro/continuous/java11.cfg

.kokoro/presubmit/java11.cfg

.kokoro/release/drop.sh

.kokoro/release/promote.sh

README.md

google-oauth-client-appengine/pom.xml

...dependencies/google-http-client-android-dependencies.html

...pendencies/google-http-client-appengine-dependencies.html

...ssembly/dependencies/google-http-client-dependencies.html

...ly/dependencies/google-http-client-gson-dependencies.html

...dependencies/google-http-client-jackson-dependencies.html

...ependencies/google-http-client-jackson2-dependencies.html

...bly/dependencies/google-http-client-jdo-dependencies.html

...ependencies/google-http-client-protobuf-dependencies.html

...bly/dependencies/google-http-client-xml-dependencies.html

...endencies/google-oauth-client-appengine-dependencies.html

...sembly/dependencies/google-oauth-client-dependencies.html

.../dependencies/google-oauth-client-java6-dependencies.html

...ependencies/google-oauth-client-servlet-dependencies.html

google-oauth-client-assembly/pom.xml