Add JSR-250 as a dependency to avoid compilation failures for Java9+

[anawara]

@togi @pettermahlen can you please review this?

[codecov-io]

Codecov Report

Merging #24 into master will not change coverage. The diff coverage is n/a.

@@            Coverage Diff            @@
##             master      #24   +/-   ##
=========================================
  Coverage     93.95%   93.95%           
  Complexity      209      209           
=========================================
  Files            23       23           
  Lines           645      645           
  Branches         93       93           
=========================================
  Hits            606      606           
  Misses           30       30           
  Partials          9        9

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[pettermahlen]

What is the impact of this change?

[pettermahlen]

Or, more precisely, what is the problem it's supposed to solve and how does it solve it?