chore(dependencies): bump spinnakerGradleVersion (#1113)

to pick up google artifact registry publishing fixes

Doing this manually rather than backporting ~7 PRs

gradle.properties

@@ -2,7 +2,7 @@ fiatVersion=1.28.0
 includeProviders=azure,gcs,oracle,redis,s3,swift,sql
 korkVersion=7.115.2
 org.gradle.parallel=true
-spinnakerGradleVersion=8.14.0
+spinnakerGradleVersion=8.23.0
 targetJava11=true
 kotlinVersion=1.4.0