update GSON to v2.8.9

Responds to https://nvd.nist.gov/vuln/detail/CVE-2022-25647 by using a patched-up version.

Author: Łukasz Paczos

gradle/dependencies.gradle

@@ -5,7 +5,7 @@ ext {
       autoValueGson    : '0.0.1',
       junit            : '4.12',
       annotation       : '1.0.0',
-      gson             : '2.8.6',
+      gson             : '2.8.9',
       retrofit         : '2.7.2',
       okhttp3          : '4.9.0',
       mockito          : '4.2.0',
@@ -63,4 +63,4 @@ ext {
       shadowJar  : "com.github.jengelman.gradle.plugins:shadow:${pluginVersion.shadowJar}",
       mapboxSdkRegistry    : "com.mapbox.gradle.plugins:sdk-registry:${pluginVersion.mapboxSdkRegistry}"
   ]
-}
+}