Upgrade to Log4j2 2.16.0

Closes gh-28986

buildSrc/build.gradle

@@ -26,7 +26,7 @@ dependencies {
 	implementation("org.springframework:spring-web:5.3.10")
 	implementation("io.spring.javaformat:spring-javaformat-gradle-plugin:${javaFormatVersion}")
 	testImplementation("org.assertj:assertj-core:3.11.1")
-	testImplementation("org.apache.logging.log4j:log4j-core:2.15.0")
+	testImplementation("org.apache.logging.log4j:log4j-core:2.16.0")
 	testImplementation("org.junit.jupiter:junit-jupiter:5.6.0")
 	testRuntimeOnly("org.junit.platform:junit-platform-launcher")
 }

spring-boot-project/spring-boot-dependencies/build.gradle

@@ -757,7 +757,7 @@ bom {
 			]
 		}
 	}
-	library("Log4j2", "2.15.0") {
+	library("Log4j2", "2.16.0") {
 		group("org.apache.logging.log4j") {
 			modules = [
 				"log4j-to-slf4j"