Overriding 'Content-Type' header with lowercase header 'content-type' produces an erroneous curl command

[jcamiel]

Hurl 4.2.0:

• Implicit Content-Type => OK

POST http://localhost:8000
{
    "name": "Bob",
    "age": 30
}
HTTP 200

$ hurl test.hurl | grep curl
* Request can be run with the following curl command:
* curl --header 'Content-Type: application/json' --data $'{\n    "name": "Bob",\n    "age": 30\n}' 'http://localhost:8000'

• Explicit "Content-Type" header on implicit => OK

POST http://localhost:8000
Content-Type: application/vnd.api+json
{
    "name": "Bob",
    "age": 30
}
HTTP 200

$ hurl test.hurl | grep curl
* Request can be run with the following curl command:
* curl --header 'Content-Type: application/vnd.api+json' --data $'{\n    "name": "Bob",\n    "age": 30\n}' 'http://localhost:8000'

• Explicit "content-type" (pay attention to the case) header on implicit => KO

POST http://localhost:8000
content-type: application/vnd.api+json
{
    "name": "Bob",
    "age": 30
}
HTTP 200

$ hurl test.hurl | grep curl
* Request can be run with the following curl command:
* curl --header 'content-type: application/vnd.api+json' --header 'Content-Type: application/json' --data $'{\n    "name": "Bob",\n    "age": 30\n}' 'http://localhost:8000'

In the last case, there are two "Content-Type" headers: 'content-type: application/vnd.api+json' and 'Content-Type: application/json'