Added Maven property for Plexus Containers version

[freemanjp]

To update all the artifacts at the same time.

[codecov]

Codecov Report

Merging #300 into master will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##             master     #300   +/-   ##
=========================================
  Coverage     83.46%   83.46%           
  Complexity       79       79           
=========================================
  Files            16       16           
  Lines           514      514           
  Branches         72       72           
=========================================
  Hits            429      429           
  Misses           39       39           
  Partials         46       46

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