fix(deps): update dependency io.micronaut:micronaut-core-bom to v4.8.12

Author: renovate[bot]

gradle/libs.versions.toml

@@ -1,7 +1,7 @@
 [versions]
 managed-jaxrs-api = "3.1.0"
 
-micronaut = "4.8.7"
+micronaut = "4.8.12"
 micronaut-docs = "2.0.0"
 micronaut-test = "4.7.0"
 micronaut-logging = "1.6.0"