openapi handler: Unable to set Accept header in operationHeaders

[cwlim]

Issue workflow progress

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• 1. The issue provides a reproduction available on Github, Stackblitz or CodeSandbox

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• 2. A failing test has been provided
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Describe the bug

Unable to set Accept header in operationHeaders when using openapi handler. I have a requirement to pass version number in Accept for example application/json;v=2 to call the right version of the API. However, it is always reverted back to application/json.

To Reproduce
.meshrc.yml

sources:
  - name: Orbit
    handler:
      openapi:
        source: https://app.orbit.love/api-docs/v1/swagger.json
        operationHeaders:
            Accept: application/json;v=2
customFetch: ./custom-fetch.ts

custom-fetch.ts

const fetch = require('node-fetch')
export default (url, options) => {
   console.table(options);
   return fetch(url, options)
}

Expected behavior

Allow Accept header

Environment:

• OS: MacOS 12.5
• @graphql-mesh/...:
• NodeJS: Node 16

Additional context