bump loggregatorlib

71f1e7e Update README.md

automatic promotion by GoCD workflow Loggregatorlib/61 > UnitTests/1 > UnitTests
automatic promotion by GoCD workflow LoggregatorIntegrationTest/151 > IntegrationTests/1 > IntegrationTests

tests passed against https://github.com/cloudfoundry/cf-release/commit/8b2ef0055c60fcd0865c807083838ef0c6a1778b