Add a job to generate churn.phar

[villfa]

Closes #126

[codecov]

Codecov Report

Merging #250 into master will decrease coverage by 0.82%.
The diff coverage is 78.26%.

@@             Coverage Diff              @@
##             master     #250      +/-   ##
============================================
- Coverage     96.38%   95.55%   -0.83%     
- Complexity      152      157       +5     
============================================
  Files            20       21       +1     
  Lines           387      405      +18     
============================================
+ Hits            373      387      +14     
- Misses           14       18       +4     

Impacted Files	Coverage Δ	Complexity Δ
src/Command/RunCommand.php	76.36% <20.00%> (-4.41%)	14.00 <2.00> (ø)
src/Process/ProcessFactory.php	94.73% <88.88%> (-5.27%)	6.00 <3.00> (+3.00)	⬇️
src/Command/AssessComplexityCommand.php	100.00% <100.00%> (ø)	2.00 <2.00> (?)

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