Set content-type in makeRequest

[eliskovets]

Description of the change

Set content-type in makeRequest, so it set it to a correct "application/json" instead of "[application/json]"

Type of change

• [x] Bug fix (non-breaking change that fixes an issue)
• [ ] Chore (cleanup or minor QOL tweak that has little to no impact on functionality)
• [ ] New feature (non-breaking change that adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)