add handling for sparse arrays

[toddtarsi]

Resolves https://github.com/mrjono1/joi-to-typescript/issues/324

[toddtarsi]

@mrjono1 - Thank you for the very impressive codebase. Please let me know if I can do anything to help expedite the process of getting this fix out, thanks!

[codecov[bot]]

Codecov Report

All modified lines are covered by tests :white_check_mark:

Comparison is base (4b689fe) 98.67% compared to head (768d10e) 98.68%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #373 +/- ## ======================================= Coverage 98.67% 98.68% ======================================= Files 9 9 Lines 529 532 +3 Branches 203 205 +2 ======================================= + Hits 522 525 +3 Misses 7 7 ``` | [Files](https://app.codecov.io/gh/mrjono1/joi-to-typescript/pull/373?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Jono) | Coverage Δ | | |---|---|---| | [src/parse.ts](https://app.codecov.io/gh/mrjono1/joi-to-typescript/pull/373?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Jono#diff-c3JjL3BhcnNlLnRz) | `97.43% <100.00%> (+0.02%)` | :arrow_up: |

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

[toddtarsi]

@mrjono1 - All requested changes are made!

[mrjono1]

Released, thankyou! https://github.com/mrjono1/joi-to-typescript/releases/tag/4.8.0

[toddtarsi]

Woohoo! Thank you @mrjono1!