Fix docker gradle build (#2142)

Co-authored-by: Elys Rivero <elys.rivero@flywire.com>

docker/spring-cloud-contract-docker/project/build.gradle

@@ -181,6 +181,7 @@ task cleanOutput(type: Delete) {
 
 task copyOutput(type: Copy) {
 	dependsOn("cleanOutput")
+	mustRunAfter("build", "generatePomFileForMavenPublication")
 	from 'build'
 	into '/spring-cloud-contract-output'
 }