Add OkHttp BOM to xapi-client for Spring Boot 3.5.7 compatibility (#307)

* Initial plan

* Add OkHttp BOM to xapi-client for Spring Boot 3.5.7 compatibility

Co-authored-by: thomasturrell <1552612+thomasturrell@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: thomasturrell <1552612+thomasturrell@users.noreply.github.com>

Author: Copilot

xapi-client/pom.xml

@@ -12,6 +12,18 @@
   <name>xAPI Client</name>
   <description>learning.dev xAPI Client</description>
 
+  <dependencyManagement>
+    <dependencies>
+      <dependency>
+        <groupId>com.squareup.okhttp3</groupId>
+        <artifactId>okhttp-bom</artifactId>
+        <version>4.12.0</version>
+        <type>pom</type>
+        <scope>import</scope>
+      </dependency>
+    </dependencies>
+  </dependencyManagement>
+
   <dependencies>
     <dependency>
       <groupId>org.springframework.boot</groupId>