Upgrade to Micrometer 1.3.1

Closes spring-projectsgh-18867

Author: wilkinsona

spring-boot-project/spring-boot-dependencies/pom.xml

@@ -151,7 +151,7 @@
 		<logback.version>1.2.3</logback.version>
 		<lombok.version>1.18.10</lombok.version>
 		<mariadb.version>2.4.4</mariadb.version>
-		<micrometer.version>1.3.0</micrometer.version>
+		<micrometer.version>1.3.1</micrometer.version>
 		<mimepull.version>1.9.12</mimepull.version>
 		<mockito.version>3.1.0</mockito.version>
 		<mongo-driver-reactivestreams.version>1.12.0</mongo-driver-reactivestreams.version>