bump guava version

pom.xml

@@ -56,7 +56,7 @@
 
         <xmemcached.version>1.4.2</xmemcached.version>
         <jedis.version>3.3.0</jedis.version>
-        <guava.version>19.0</guava.version>
+        <guava.version>29.0-jre</guava.version>
         <guice.version>3.0</guice.version>
 
         <httpcore.version>4.4.12</httpcore.version>