Add http1_title_case_headers support to reqwest http client

[shahar3012]

Some HTTP server implementations don't follow HTTP 1.1 standard:

HTTP header fields, which include general-header (section 4.5), request-header (section 5.3), response-header (section 6.2), and entity-header (section 7.1) fields, follow the same generic format as that given in Section 3.1 of RFC 822 [9]. Each header field consists of a name followed by a colon (":") and the field value. Field names are case-insensitive.

Reqwest default behavior is lowercase headers, which might result in errors from some HTTP servers that don't follow HTTP 1.1 standard.
To avoid it, this PR uses the http1_title_case_headers function to add support for case-sensitive HTTP headers.

[lovasoa]

thanks !

[lovasoa]

published as v2.12.4