Motivation:
In https://datatracker.ietf.org/doc/html/rfc7540#section-10.3 it says that only certain characters are valid in a header value:

> Any request or response that contains a character not permitted
> in a header field value MUST be treated as malformed (Section 8.1.2.6).
> Valid characters are defined by the "field-content" ABNF rule in
> Section 3.2 of [RFC7230].

Modification:
Add a header value validation step to HpackDecoder.

Result:
Header values are now validated against the Section 10.3, etc. rules.

…ion fails

…ng header names and values