CanonicalURLMiddleware default to all environments

Having a Live/Prod only feature sets people up for bugs. 
A common scenario for this one is a javascript feature that requests from an API - its easy to forget a trailing slash in this scenario and it will work on your local an your test environment - failing only once you deploy it to prod. I'd suggest we turn this on everywhere except the CLI by default (or, disable it by default).

src/Control/Middleware/CanonicalURLMiddleware.php

@@ -81,7 +81,9 @@ class CanonicalURLMiddleware implements HTTPMiddleware
      * @var array|bool
      */
     protected $enabledEnvs = [
-        CoreKernel::LIVE
+        CoreKernel::LIVE,
+        CoreKernel::TEST,
+        CoreKernel::DEV,
     ];
 
     /**