m2e egit connector (for SCM) on Eclipse Photon failure

I had the same problem. I managed to get it installed by going to Help -> Install New Software -> Work with: https://repo1.maven.org/maven2/.m2e/connectors/m2eclipse-egit/0.15.1/N/0.15.1.201806191431/

It seems to have installed without any problems, but I must admit, I haven't actually used it yet.