Add label exclusion support.

[chinthakagodawita]

This takes #16 and converts it to Typescript.

Closes #16.

[codecov]

Codecov Report

Merging #86 (1a152b3) into master (3422469) will increase coverage by 0.07%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master      #86      +/-   ##
==========================================
+ Coverage   98.76%   98.83%   +0.07%     
==========================================
  Files           3        3              
  Lines         405      431      +26     
  Branches       80       64      -16     
==========================================
+ Hits          400      426      +26     
- Misses          0        5       +5     
+ Partials        5        0       -5     

Impacted Files	Coverage Δ
src/autoupdater.ts	98.40% <100.00%> (+0.08%)	⬆️
src/config-loader.ts	100.00% <100.00%> (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 3422469...1a152b3. Read the comment docs.

[chinthakagodawita]

Thanks @anarast !