Replace use of of unsigned char* with fmt

Using unsigned char* or signed char* results in a deprecation warning, which is treated as an error.  It needs to be casted to regular char* for it to work.

Source/Core/Common/HttpRequest.cpp

@@ -228,7 +228,8 @@ HttpRequest::Response HttpRequest::Impl::Fetch(const std::string& url, Method me
     else
     {
       ERROR_LOG_FMT(COMMON, "Failed to {} {}: server replied with code {} and body\n\x1b[0m{:.{}}",
-                    type, url, response_code, buffer.data(), static_cast<int>(buffer.size()));
+                    type, url, response_code, reinterpret_cast<char*>(buffer.data()),
+                    static_cast<int>(buffer.size()));
     }
     return {};
   }