fix: add support for custom plugins

[mrlubos]

Closes https://github.com/hey-api/openapi-ts/issues/1236

[stackblitz[bot]]

Run & review this pull request in StackBlitz Codeflow.

[changeset-bot[bot]]

🦋 Changeset detected

Latest commit: 00253bcfdd6fe68496a2d84df91a37187b86ab16

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

| Name | Type | | ------------------- | ----- | | @hey-api/openapi-ts | Patch |

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[vercel[bot]]

The latest updates on your projects. Learn more about Vercel for Git ↗︎

Name	Status	Preview	Comments	Updated (UTC)
hey-api-docs	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Nov 8, 2024 3:50am

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 78.94737% with 8 lines in your changes missing coverage. Please review.

Project coverage is 67.71%. Comparing base (404690c) to head (07800d4). Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
packages/openapi-ts/src/index.ts	78.94%	8 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #1251 +/- ## ======================================= Coverage 67.71% 67.71% ======================================= Files 132 132 Lines 19499 19528 +29 Branches 1751 1755 +4 ======================================= + Hits 13203 13224 +21 - Misses 6292 6300 +8 Partials 4 4 ``` | [Flag](https://app.codecov.io/gh/hey-api/openapi-ts/pull/1251/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=hey-api) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/hey-api/openapi-ts/pull/1251/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=hey-api) | `67.71% <78.94%> (+<0.01%)` | :arrow_up: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=hey-api#carryforward-flags-in-the-pull-request-comment) to find out more.

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