Bump com.google.guava:guava from 18.0 to 23.0

Bumps [com.google.guava: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)

---
updated-dependencies:
- dependency-name: com.google.guava:guava
  dependency-version: '23.0'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

build.gradle

@@ -323,7 +323,7 @@ dependencies {
 	}
 	implementation('com.fasterxml.jackson.core:jackson-annotations:2.2.3')
 	implementation('com.fasterxml.jackson.core:jackson-databind:2.2.3')
-	implementation('com.google.guava:guava:18.0')
+	implementation('com.google.guava:guava:23.0')
 	implementation('com.googlecode.jsonschema2pojo:jsonschema2pojo-core:0.3.6')
 	implementation('com.j2html:j2html:0.7') {
 		exclude group: 'junit', module: 'junit' // bro