Please switch SuppliedSchema to an owned string

[kitsuneninetails]

Using a &`static str means that the string supplied to the schema must be a string known at compile time and created at program execution (akin to a static const char* in C). This disallows reading a schema in from a file.

Looking at how SuppliedSchema uses it's string, it's not obvious that a static string is needed or why an owned string should not be used. In terms of performance, this is a one-time operation or thereabouts, and is not a repeated call, and usually upon program initiation, meaning super-high performance isn't really a factor.

Using an owned string is more usable and transparent and allows for more flexibility in the use of SuppliedSchema

A proposed fix is in an upcoming PR.

[gklijs]

Fixed by @kitsuneninetails