Change wasi:clocks from include to import

wit/proxy.wit

@@ -4,7 +4,8 @@ package wasi:[email protected];
 /// It is intended to be `include`d in other worlds.
 world imports {
   /// HTTP proxies have access to time and randomness.
-  include wasi:clocks/imports@0.2.0;
+  import wasi:clocks/monotonic-clock@0.2.0;
+  import wasi:clocks/wall-clock@0.2.0;
   import wasi:random/random@0.2.0;
 
   /// Proxies have standard output and error streams which are expected to