Build and publish locally the `common` artifact. (#159)
Build and publish locally the `common` artifact. (#159)

The Update Gradle Wrapper action requires the project(s) to be in a
buildable state to be able to update the Wrapper script.
As a preliminary step, we build the `common` artifact which is shared
across many projects (it is then published locally to ~/.m2 folder).
spring-cloud-samples/spring-cloud-contract-samples,spring-cloud-samples/spring-cloud-contract-samples,spring-cloud-samples/spring-cloud-contract-samples,spring-cloud-samples/spring-cloud-contract-samples,spring-cloud-samples/spring-cloud-contract-samples