Update MaxMind geoip2 version to 2.6

Update to align with #16801 jackson 2.7.1

plugins/ingest-geoip/build.gradle

@@ -23,11 +23,11 @@ esplugin {
 }
 
 dependencies {
-  compile ('com.maxmind.geoip2:geoip2:2.4.0')
+  compile ('com.maxmind.geoip2:geoip2:2.6.0')
   // geoip2 dependencies:
-  compile('com.fasterxml.jackson.core:jackson-annotations:2.5.0')
-  compile('com.fasterxml.jackson.core:jackson-databind:2.5.3')
-  compile('com.maxmind.db:maxmind-db:1.0.1')
+  compile('com.fasterxml.jackson.core:jackson-annotations:2.7.1')
+  compile('com.fasterxml.jackson.core:jackson-databind:2.7.1')
+  compile('com.maxmind.db:maxmind-db:1.2.0')
 
   testCompile 'org.elasticsearch:geolite2-databases:20151029'
 }
@@ -60,4 +60,4 @@ thirdPartyAudit.excludes = [
   'com.google.api.client.http.HttpResponseException',
   'com.google.api.client.http.javanet.NetHttpTransport',
   'com.google.api.client.http.javanet.NetHttpTransport',
-]
+]