Bump guava from 18.0 to 23.0 (#84)

Bumps [guava](https://github.com/google/guava) from 18.0 to 23.0.
- [Release notes](https://github.com/google/guava/releases)
- [Commits](google/guava@v18.0...v23.0)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

pom.xml

@@ -245,7 +245,7 @@
         <dependency>
             <groupId>com.google.guava</groupId>
             <artifactId>guava</artifactId>
-            <version>18.0</version>
+            <version>23.0</version>
         </dependency>
     </dependencies>