Checks

• I understand project setup issues should be asked on StackOverflow or in GitHub Discussions.
• I updated to latest http-proxy-middleware.

Describe the bug (be clear and concise)

fixRequestBody not work，proxyReq.getHeader('Content-Type') result is application/x-www-form-urlencoded; charset=UTF-8

but code is if (contentType === 'application/x-www-form-urlencoded') so not work.

Step-by-step reproduction instructions

none

Expected behavior (be clear and concise)

none

How is http-proxy-middleware used in your project?

none

What http-proxy-middleware configuration are you using?

none

What OS/version and node/version are you seeing the problem?

node16 ubunt18.04

Additional context (optional)

No response