fix typo (#87)

s/endpoing/endpoint

cors.go

@@ -384,7 +384,7 @@ func (c *Cors) isOriginAllowed(r *http.Request, origin string) bool {
 }
 
 // isMethodAllowed checks if a given method can be used as part of a cross-domain request
-// on the endpoing
+// on the endpoint
 func (c *Cors) isMethodAllowed(method string) bool {
 	if len(c.allowedMethods) == 0 {
 		// If no method allowed, always return false, even for preflight request