Latest esbuild removes watch flag in build option

According to [release notes of v0.17.0](https://github.com/evanw/esbuild/releases/tag/v0.17.0), `watch` option is removed and it cause `bundle-require` to error:

```
✘ [ERROR] Invalid option in build() call: "watch"

/Users/otakustay/Develop/reskript/node_modules/.pnpm/esbuild@0.17.4/node_modules/esbuild/lib/main.js:255:12:
255 │ throw new Error(`Invalid option ${where}: ${quote(key)}`);
╵ ^

at checkForInvalidFlags (.node_modules/.pnpm/esbuild@0.17.4/node_modules/esbuild/lib/main.js:255:13)
at flagsForBuildOptions (.node_modules/.pnpm/esbuild@0.17.4/node_modules/esbuild/lib/main.js:457:3)
at buildOrContextContinue (.node_modules/.pnpm/esbuild@0.17.4/node_modules/esbuild/lib/main.js:1009:9)
at .node_modules/.pnpm/esbuild@0.17.4/node_modules/esbuild/lib/main.js:983:11
```

To be compatible with multiple version of esbuild, maybe we can make a new option, allow users to pass `esbuild.build` function directly?