Upgrade Micrometer to 1.0.0.rc6

Fixes #340

Author: acogoluegnes

pom.xml

@@ -56,7 +56,7 @@
 
     <slf4j.version>1.7.21</slf4j.version>
     <metrics.version>3.1.2</metrics.version>
-    <micrometer.version>1.0.0-rc.2</micrometer.version>
+    <micrometer.version>1.0.0-rc.6</micrometer.version>
     <logback.version>1.1.7</logback.version>
     <commons-cli.version>1.1</commons-cli.version>
     <junit.version>4.12</junit.version>