feat: inject versions into friendly errors

[tabrindle]

In your error message, you can include {{wantedVersion}} and {{installedVersion}} to give the user version information, or even to customize scripts to help them install or update.

  "Yarn": [
    {
      "rule": "cli",
      "binary": "yarn",
      "error": "You have yarn@{{installedVersion}}, and need yarn@{{wantedVersion}}. Fix with `npm install -g yarn@{{wantedVersion}}`"
    }
  ]

[codecov]

Codecov Report

Merging #195 into master will increase coverage by 0.12%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #195      +/-   ##
==========================================
+ Coverage   80.76%   80.88%   +0.12%     
==========================================
  Files          33       33              
  Lines         629      633       +4     
  Branches      108      111       +3     
==========================================
+ Hits          508      512       +4     
  Misses         83       83              
  Partials       38       38

Impacted Files	Coverage Δ
src/extensions/functions/checkCLI.ts	89.47% <100%> (+2.8%)	⬆️

---

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 dfe8fd8...39fe7a6. Read the comment docs.

[GantMan]

you're one of the few people I know who knows emptystring evaluates as falsy.

[GantMan]

works for me! Thanks so much @tabrindle