Added HTTP Request header normalizer

Added interceptor NormalizeHTTPRequestHeaders to capture the headers (single and multi-value) sent in the API Gateway (HTTP) request and normalizes them to either an all-lowercase form or to their canonical form (content-type as opposed to Content-Type) based on the value of the given 'canonical' parameter

Improved handling of uncaught HTTP errors

Added improved error handling capabilities to handle HTTP errors and create a proper HTTP response for them

v0.3.0

Added interceptor for JSON Schema validation

Improved documentation for AddSecurityHeaders interceptor

v0.2.1

Better README

v0.2.0

Added Interceptor to include security headers in the response