Bump GSON version to 2.9.1 to get rid of a vulnerability (#29)

This is the vuln: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-25647

Author: pawel-mikolajczyk

jazon-core/build.gradle

@@ -6,10 +6,10 @@ ext {
 apply from: '../gradle/publishing.gradle'
 
 dependencies {
-    compile group: 'com.google.code.gson', name: 'gson', version: '2.8.5'
+    compile group: 'com.google.code.gson', name: 'gson', version: '2.9.1'
 
     compileOnly 'org.projectlombok:lombok:1.18.12'
     annotationProcessor 'org.projectlombok:lombok:1.18.12'
 
     testCompile group: 'org.spockframework', name: 'spock-core', version: '1.2-groovy-2.4'
-}
+}