chore(javadocs): include google tag manager (#4673)

related to: camunda/team-automation-platform/issues/160

pom.xml

@@ -134,10 +134,18 @@
             <groupId>org.apache.maven.plugins</groupId>
             <artifactId>maven-javadoc-plugin</artifactId>
             <configuration>
+              <top><![CDATA[
+                <script>(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':
+                  new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],
+                  j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src=
+                  'https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);
+                  })(window,document,'script','dataLayer','GTM-PP9MHKW');</script>
+              ]]></top>
               <failOnError>false</failOnError>
               <additionalJOptions>
                 <additionalJOption>-Xdoclint:none</additionalJOption>
                 <additionalJOption>--ignore-source-errors</additionalJOption>
+                <additionalJOption>--allow-script-in-comments</additionalJOption>
               </additionalJOptions>
               <doctitle>Camunda Platform Javadocs ${project.version}</doctitle>
               <windowtitle>Camunda Platform Javadocs ${project.version}</windowtitle>