fix(deps): update dependency com.uber.nullaway:nullaway to v0.12.15

Author: renovate[bot]

gradle/templates.versions.toml

@@ -54,7 +54,7 @@ micronaut-build-plugins = "7.6.6"
 micronaut-gradle-plugin = "4.6.1"
 mockserver-client-java = "5.15.0"
 mockk = "1.13.17"
-nullaway = "0.12.12"
+nullaway = "0.12.15"
 protobuf-gradle-plugin = "0.9.2"
 rewrite-gradle-plugin = "6.29.4"
 rewrite-maven-plugin = "5.47.3"