Charset at Multipart Form header

[fkesheh]

According to this discussion thread owasp-modsecurity/ModSecurity#1900 having a charset= parameter in that Content-Type header appears to be contrary to the standard, so ModSecurity is blocking it.

Feign add it by default:

feign-form/feign-form/src/main/java/feign/form/MultipartFormContentProcessor.java

Line 94 in 98e51d1

.append("; charset=").append(charset.name())

Could that become optional or configurable?