fixes client using unsupported version of Socket.IO protocols (#368)

Author: twick00

setup.py

@@ -68,6 +68,7 @@
  "pygdbmi>=0.10.0.0b0, <0.11", # parse gdb output
  "Pygments>=2.2.0, <3.0", # syntax highlighting
  "greenlet==0.4.16",
+ "python-socketio>=4.6.1, <5.0", # pinned to use socketio 2 under the hood (issue #366)
  ],
  classifiers=[
  "Intended Audience :: Developers",