Note Julia version compatibility in the README.

Author: ViralBShah

README.md

@@ -20,6 +20,9 @@ It has three modes of operation
 - All processes are part of both the MPI as well as Julia cluster. MPI is used as the transport
   for julia messages. This is useful on environments which do not allow TCP/IP connectivity
   between worker processes
+  
+Note: This package works with Julia 1.0, 1.1 and 1.2. It is broken for Julia 1.3, 1.4.0, and 1.4.1, but
+works with Julia 1.4.2 and later releases.
 
 ### MPIManager: only workers execute MPI code