fix!: support forks

[Weetbix]

Follow up to @npentrel 's PR here: #49 🙌

Overall changes the action to rely on the @actions/checkout action to fetch the git history and use the commit shas. Previously it would fetch manually using git inside the action, and fetch from origin which breaks for fork PRs.

Additions:

• Update readme to specify fetch-depth: 0 when using checkout, so that the action has access to the git history
  • Update test workflow
• Add light logging of what the action is doing

I will release as a breaking change as we no longer fetch in the action.

fixes #48
supersedes #49

[github-actions]

Overall readability score: 31.93 (🟢 +0)

File	Readability
README.md	56.32 (🟢 +0)

View detailed metrics

🟢 - Shows an increase in readability
🔴 - Shows a decrease in readability

File	Readability	FRE	GF	ARI	CLI	DCRS
README.md	56.32	45.05	9.43	14.7	12.93	6.86
	🟢 +0	🟢 +0	🟢 +0	🟢 +0	🟢 +0	🟢 +0

Averages:

	Readability	FRE	GF	ARI	CLI	DCRS
Average	31.93	16.05	14.96	15.45	15.06	8.73
	🟢 +0	🟢 +0	🟢 +0	🟢 +0	🟢 +0	🟢 +0

View metric targets

Metric	Range	Ideal score
Flesch Reading Ease	100 (very easy read) to 0 (extremely difficult read)	60
Gunning Fog	6 (very easy read) to 17 (extremely difficult read)	8 or less
Auto. Read. Index	6 (very easy read) to 14 (extremely difficult read)	8 or less
Coleman Liau Index	6 (very easy read) to 17 (extremely difficult read)	8 or less
Dale-Chall Readability	4.9 (very easy read) to 9.9 (extremely difficult read)	6.9 or less

[npentrel]

Thanks folks!