Bump io.gsonfire:gson-fire from 1.8.4 to 1.9.0

Bumps [io.gsonfire:gson-fire](https://github.com/julman99/gson-fire) from 1.8.4 to 1.9.0.
- [Release notes](https://github.com/julman99/gson-fire/releases)
- [Commits](https://github.com/julman99/gson-fire/commits/v1.9.0)

---
updated-dependencies:
- dependency-name: io.gsonfire:gson-fire
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

build.gradle

@@ -103,7 +103,7 @@ dependencies {
     compile 'com.squareup.okhttp3:okhttp:3.14.7'
     compile 'com.squareup.okhttp3:logging-interceptor:3.14.7'
     compile 'com.google.code.gson:gson:2.8.6'
-    compile 'io.gsonfire:gson-fire:1.8.4'
+    compile 'io.gsonfire:gson-fire:1.9.0'
     compile group: 'org.apache.commons', name: 'commons-lang3', version: '3.10'
     compile 'org.threeten:threetenbp:1.4.3'
     testCompile 'junit:junit:4.13'