Implement output markdown

[raimon49]

• Implement function
• Testing
• Add a document
• Bump version
• Release to PyPI

[codecov]

Codecov Report

Merging #3 into master will increase coverage by 0.46%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master       #3      +/-   ##
==========================================
+ Coverage   95.45%   95.91%   +0.46%     
==========================================
  Files           1        1              
  Lines          88       98      +10     
==========================================
+ Hits           84       94      +10     
  Misses          4        4

Impacted Files	Coverage Δ
piplicenses.py	95.91% <100%> (+0.46%)	⬆️

---

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 0b81dca...0d8ef19. Read the comment docs.