fix(deps): update dependency io.micronaut:micronaut-core-bom to v4.8.1 (#550)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

gradle/libs.versions.toml

@@ -16,7 +16,7 @@
 # a managed version (a version which alias starts with "managed-"
 
 [versions]
-micronaut = "4.7.12"
+micronaut = "4.8.1"
 micronaut-docs = "2.0.0"
 micronaut-test = "4.6.2"
 groovy = "4.0.24"