chore(dependencies): Autobump spinnakerGradleVersion (spinnaker#1773)

Co-authored-by: root <root@6a807b439d68>

gradle.properties

@@ -3,7 +3,7 @@ fiatVersion=1.22.0
 front50Version=2.21.0
 korkVersion=7.59.0
 org.gradle.parallel=true
-spinnakerGradleVersion=8.4.0
+spinnakerGradleVersion=8.5.0
 
 # To enable a composite reference to a project, set the
 #  project property `'<projectName>Composite=true'`.