Align retrofit2 converter-gson with retrofit.version (#541)

converter-gson was pinned to 2.9.0 in both the parent dependencyManagement
and analytics/pom.xml while retrofit and retrofit-mock use 2.11.0, which
fails Maven DependencyConvergence for consumers. Supersedes #513, which
only changed the parent and left the module-level pin in place.

Co-authored-by: t <t@t>

Author: MichaelGHSeg

analytics/pom.xml

@@ -59,7 +59,7 @@
     <dependency>
       <groupId>com.squareup.retrofit2</groupId>
       <artifactId>converter-gson</artifactId>
-      <version>2.9.0</version>
+      <version>${retrofit.version}</version>
     </dependency>
     <dependency>
       <groupId>com.squareup.retrofit2</groupId>

pom.xml

@@ -85,7 +85,7 @@
       <dependency>
         <groupId>com.squareup.retrofit2</groupId>
         <artifactId>converter-gson</artifactId>
-        <version>2.9.0</version>
+        <version>${retrofit.version}</version>
       </dependency>
       <dependency>
         <groupId>com.squareup.retrofit2</groupId>