Issue Summary

When making an API request that has some uppercase letters in the application/json Content-Type header (e.g. Application/JSON, or application/Json, etc), the request returns a 500 response.

Steps to Reproduce

1. Run an API call like the following to update the title of an open PR in a Bitbucket Cloud repo

   curl -u username:app_password --request PUT \
   --url 'https://api.bitbucket.org/2.0/repositories/workspace-id/repo-slug/pullrequests/23' \
   --header 'Accept: application/json' \
   --header 'Content-Type: Application/JSON' \
   --data '{
   "title": "Updated PR title"
   }'
   

Expected Results

The request succeeds.

Actual Results

The request returns a 500 error with the message "Something went wrong".

Workaround

Use lowercase in the application/json Content-Type header:

curl -u username:app_password --request PUT \
--url 'https://api.bitbucket.org/2.0/repositories/workspace-id/repo-slug/pullrequests/23' \
--header 'Accept: application/json' \
--header 'Content-Type: application/json' \
--data '{
"title": "Updated PR title"
}'