config: bump guava to 23.5
diff --git a/pom.xml b/pom.xml
index cf8452a..e285827 100644
--- a/pom.xml
+++ b/pom.xml
@@ -271,7 +271,7 @@
     <dependency>
       <groupId>com.google.guava</groupId>
       <artifactId>guava</artifactId>
-      <version>23.4-jre</version>
+      <version>23.5-jre</version>
     </dependency>
     <dependency>
       <groupId>org.apache.ant</groupId>