docs: modify sample url in compression's README.md (webpack#1640)

Author: hiroppy

examples/cli/compression/README.md

@@ -11,7 +11,7 @@ npm run webpack-dev-server -- --open --compress
 
 ## What should happen
 
-1. The script should open `https://localhost:8080/`.
+1. The script should open `http://localhost:8080/`.
 2. Files being sent to the browser from the `webpack` bundle should be gzipped.
 3. Open the console in your browser's devtools and select the _Network_ tab.
 4. Find `bundle.js`. The response headers should contain `Content-Encoding: gzip`.