Update dependency com.google.code.gson:gson to v2.12.0

Author: renovate[bot]

build.gradle

@@ -36,7 +36,7 @@ dependencies {
     implementation group: 'org.bitbucket.b_c', name: 'jose4j', version: '0.7.9'
 
     // For parsing JSON
-    testImplementation group: 'com.google.code.gson', name: 'gson', version: '2.8.9'
+    testImplementation group: 'com.google.code.gson', name: 'gson', version: '2.12.0'
 
     // For making HTTP requests
     testImplementation group: 'org.apache.httpcomponents', name: 'fluent-hc', version: '4.5.13'