Add basic support for templating (#21)

Make middleware asynchronous

Update package syntax to 5.2

Update README.md

Update pr-test.yml

Make middleware return result instead of Void (#15)

This commit aims to make working with custom middleware a little less error-prone. Thanks to @jnutting for the feedback and pitch.

The changes introduced add a requirement for middleware to return a result, which will put the compiler to work and help avoid human-error.

Fix path in example

Add support for path and query parameters (#6)

Closes #4

Add GitHub action for testing