Electron-forge: Invalid options object when running `electron-forge start`

Preflight Checklist

• [x] I have read the contribution documentation for this project.
• [x] I agree to follow the code of conduct that this project follows, as appropriate.
• [x] I have searched the issue tracker for a bug that matches the one I want to file, without success.

Issue Details

• Electron Forge Version:
  
  
  
  • 6.0.0-beta.55
  
  
• Electron Version:
  
  
  
  • 11.4.1
  
  
• Operating System:
  
  
  
  • Windows 10
  
  
• Last Known Working Electron Forge version::
  
  
  
  • 6.0.0-beta.54
  
  

Expected Behavior

Running the Electron app in dev mode should work.

Actual Behavior

When running electron-forge start it prints the following output:

√ Checking your system
√ Locating Application
√ Preparing native dependencies: 1 / 1
√ Compiling Main Process Code
× Launch Dev Servers

An unhandled error has occurred inside Forge:
Invalid options object. Dev Middleware has been initialized using an options object that does not match the API schema.
 - options has an unknown property 'historyApiFallback'. These properties are valid:
   object { mimeTypes?, writeToDisk?, methods?, headers?, publicPath?, stats?, serverSideRender?, outputFileSystem?, index? }
ValidationError: Invalid options object. Dev Middleware has been initialized using an options object that does not match the API schema.
 - options has an unknown property 'historyApiFallback'. These properties are valid:
   object { mimeTypes?, writeToDisk?, methods?, headers?, publicPath?, stats?, serverSideRender?, outputFileSystem?, index? }
    at validate (<project-path>\electron\node_modules\webpack-dev-middleware\node_modules\schema-utils\dist\validate.js:104:11)
    at wdm (<project-path>\electron\node_modules\webpack-dev-middleware\dist\index.js:29:29)
    at <project-path>\electron\node_modules\@electron-forge\plugin-webpack\src\WebpackPlugin.ts:292:22
    at processTicksAndRejections (internal/process/task_queues.js:93:5)

I updated electron-forge from 6.0.0-beta.54 to 6.0.0-beta.55 and did not change any configuration.

To Reproduce

Additional Information