uplift guava to 27.1-jre

Author: Emil-Gustafsson

build.gradle

@@ -17,7 +17,7 @@ dependencies {
     compile group: 'org.slf4j', name: 'slf4j-api', version: '1.7.26'
     compile group: 'org.zeromq', name: 'jeromq', version:'0.4.0'
     compile group: 'com.google.code.gson', name: 'gson', version:'2.8.5'
-    compile group: 'com.google.guava', name: 'guava', version: '24.0-jre'
+    compile group: 'com.google.guava', name: 'guava', version: '27.1-jre'
     compile group: 'com.fasterxml.jackson.core', name: 'jackson-databind', version:'2.9.8'
     testCompile group: 'junit', name: 'junit', version: '4.12'