Install missing multilayer_join_node.hpp header

[olantwin]

This header isn't installed, but pulled in by several of the installed headers.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

@@           Coverage Diff           @@
##             main     #400   +/-   ##
=======================================
  Coverage   83.71%   83.71%           
=======================================
  Files         126      126           
  Lines        3291     3291           
  Branches      583      583           
=======================================
  Hits         2755     2755           
  Misses        325      325           
  Partials      211      211           

Flag	Coverage Δ
unittests	83.71% <ø> (ø)

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[knoepfel]

Thanks, @olantwin, for catching this error! The multilayer_join_node is not yet in released code, so this will not affect anyone testing the Phlex v0.1.0 prototype. This is a necessary change, however, for v0.2.0 to be released later this month.

[olantwin]

No problem! I ran into some limitations with v0.1.0 which were fixed in master, so moved my prototyping to the master branch for the time being. Looking forward to v0.2.0!