feat: support healthcheck rfc draft 06

* Update MIME type of health checks to match latest draft

* Fix a typo: heath -> health

feat: consistent error messages and descriptions

messages are shorter showing what is wrong, descriptions are longer explaining why.

fix: match() error on petstore resolved

No longer getting this error with the more performant syntax avoiding the invalid .[ usage

perf: avoid .[ and just use [

related to performance discovery in IBM/openapi-validator#508

feat: new rule to restrict media types in paths (#31)

* feat: add rule for no media types in resources

New rule to address: #24

* Added more media types to description

* Added more tests

* feat: add rule for no media types in resources

New rule to address: #24

* Added more media types to description

* Added more tests

* Update src/ruleset.ts

* Update src/ruleset.ts

reduce code duplication on regex

Co-authored-by: Phil Sturgeon <67381+philsturgeon@users.noreply.github.com>

* tests-added-oas2-tests

Added tests for OAS2 api definitions and removed old test

Co-authored-by: Phil Sturgeon <67381+philsturgeon@users.noreply.github.com>

feat: add rule for api must have a securitySchemes defined (#35)

fix: amend CommonJS output to be compatible with `require` (#36)

Add `module.exports = module.exports.default;` at the end of the CJS file.
Example:

```js
const ruleset = require('@apisyouwonthate/style-guide');
```

fix: include esm bundle

fix: mark @stoplight/types as an internal pkg

fix: switched builds to tsup