Use ssh protocol for developer connection

I don't want to create an alternate authentication configuration for
command line git operations over HTTP.  Plugins with automated releases
do not need the plugin maintainer to push to the repository from a `mvn`
command.  Because the git client plugin still uses manual releases,
I need to keep the ssh  authentication method for developer push.

pom.xml

@@ -47,7 +47,7 @@
 
   <scm>
     <connection>scm:git:https://github.com/${gitHubRepo}</connection>
-    <developerConnection>scm:git:https://github.com/${gitHubRepo}</developerConnection>
+    <developerConnection>scm:git:git@github.com:${gitHubRepo}.git</developerConnection>
     <tag>${scmTag}</tag>
     <url>https://github.com/${gitHubRepo}</url>
   </scm>