fix: skip deployment on forks

[peaceiris]

Fixes #153

[corollari]

I've checked the code and while it looks good to me, I thought that it may be better if instead of reporting that the action was successful, as it does right now, it reported the action as skipped, like in the following screenshot:

I've investigated ways to achieve that and it seems that currently the only way to do it is by setting an if condition that evaluates to false. In a previous version of github actions it was possible to achieve that result by returning the number 78^[1], but that was removed^[2] in a later version, an as of right now and action can only report success or failure^[3]. Github staff have said that they are working on an alternative^[2], but I haven't been able to find any info on that and I believe that hasn't been implemented.

All in all, I believe that is not something currently achievable and the current implementation is good, just wanted to document my investigation to prevent other people wasting time on this.

[1] https://github.saobby.my.eu.orgmunity/t5/GitHub-Actions/GitHub-Actions-quot-neutral-quot-exit-code-is-incorrectly/td-p/29051
[2] https://twitter.com/ethomson/status/1163899559279497217
[3] https://help.github.com/en/actions/reference/development-tools-for-github-actions#setting-an-actions-status-using-exit-codes

[peaceiris]

Thank you for investigating the neutral exit code.

I also know that we could set neutral status by action side in GitHub Actions beta v1. Unfortunately, we have no way to set neutral from GitHub Actions was beta v2. This is one of the most expected features for all GitHub Actions users. I hope this feature will be implemented.

[codecov]

Codecov Report

Merging #156 into master will increase coverage by 1.16%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #156      +/-   ##
==========================================
+ Coverage   51.86%   53.03%   +1.16%     
==========================================
  Files           4        4              
  Lines         241      247       +6     
  Branches       40       42       +2     
==========================================
+ Hits          125      131       +6     
  Misses        116      116

Impacted Files	Coverage Δ
src/utils.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 ff31e77...2292986. Read the comment docs.