build: Add Splunk repository to repositories for Maven FP automation (#7344)

Author: aikebah

.github/workflows/files/maven-pom.middle

@@ -49,6 +49,11 @@
             <name>gradle</name>
             <url>https://plugins.gradle.org/m2/</url>
         </repository>
+        <repository>
+            <id>splunk-artifactory</id>
+            <name>Splunk Releases</name>
+            <url>https://splunk.jfrog.io/splunk/ext-releases-local</url>
+        </repository>
         <repository>
             <id>vaadin-addon</id>
             <name>vaadin addons</name>