fix: pom.xml to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JAVA-ORGJETBRAINSKOTLIN-2393744

Author: snyk-bot

pom.xml

@@ -42,7 +42,7 @@
         <java.version>8</java.version>
         <kotlin.version>1.7.20</kotlin.version>
         <spotless.version>2.27.2</spotless.version>
-        <retrofit.version>2.9.0</retrofit.version>
+        <retrofit.version>2.12.0</retrofit.version>
         <auto.version>1.10.4</auto.version>
         <gson.version>2.10.1</gson.version>
         <okhttp.version>4.12.0</okhttp.version>