Add new has-command output parameter

[xt0rted]

This builds on #136 and adds a new has-command out parameter that can be used to check if the job should continue or not.

[codecov]

Codecov Report

Merging #137 into master will increase coverage by 0.15%.
The diff coverage is 100%.

@@            Coverage Diff            @@
##           master    #137      +/-   ##
=========================================
+ Coverage   86.74%   86.9%   +0.15%     
=========================================
  Files           5       5              
  Lines          83      84       +1     
  Branches       11      11              
=========================================
+ Hits           72      73       +1     
  Partials       11      11

Flag	Coverage Δ
#unittests	86.9% <100%> (+0.15%)	⬆️

Impacted Files	Coverage Δ
src/main.ts	100% <100%> (ø)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 3a57d7f...f2335b4. Read the comment docs.