Don't fail Actions Workflow when no mutation testing is performed (#827)

`pitest-github` gradle task will fail by default if no mutation testing is performed.

This will occur when a PR is raised which doesn't change any production code. e.g. docs, tests only etc.

Author: Adrian Clay

service/build.gradle

@@ -152,11 +152,14 @@ pitest {
 	// git feature limits analysis to contents of PR only
 	features = ["+GIT(from[HEAD~1])"]
 
+	// PRs which don't introduce any production code changes, shouldn't fail the Mutation Testing Actions Workflow
+        failWhenNoMutations = false
+
 	mutators = ['STRONGER', 'EXTENDED_ALL']
 
 	threads = project.getGradle().getStartParameter().getMaxWorkerCount()
 }
 
 bootJar {
 	exclude("**/TransformJsonToXml*")
-}
+}