fix readme badge URLs
Stabilize tests and bump etcd libraries [#74312764]

* Etcd (and libraries) bump to versions currently in cf-release
* Refactor and improve stability of store tests

Signed-off-by: John Tuley <jtuley@pivotallabs.com>
bump loggregatorlib

automatic promotion by GoCD workflow Loggregatorlib/7 > UnitTests/1 > UnitTests
merge from develop

fix merge conflict from GoCD workflow Loggregator/54 > IntegrationTests/1 > IntegrationTests

tests passed against https://github.com/cloudfoundry/cf-release/commit/b11f40ae5083902c19cc08c2c0e94adc7142dc84