(v4.1.x): Bump org.springframework.boot from 3.1.7 to 3.1.8

Bumps org.springframework.boot from 3.1.7 to 3.1.8.

---
updated-dependencies:
- dependency-name: org.springframework.boot
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

settings.gradle

@@ -23,7 +23,7 @@ pluginManagement {
 		}
 	}
 	plugins {
-		id "org.springframework.boot" version "3.1.7"
+		id "org.springframework.boot" version "3.1.8"
 		id "io.spring.nohttp" version "0.0.11"
 		id 'org.asciidoctor.jvm.pdf'
 		id 'org.asciidoctor.jvm.convert'