Use loaderUtils.stringifyRequest

Since webpack calculates the hash before module paths are translated into module ids, we must avoid absolute paths to ensure consistent hashes across different compilations.

loader.js

@@ -13,7 +13,7 @@ module.exports = function(content) {
   return content + `
     if(module.hot) {
       // ${Date.now()}
-      const cssReload = require('${require.resolve('./hotModuleReplacement')}')(${JSON.stringify(options)});
+      const cssReload = require(${loaderUtils.stringifyRequest(this, require.resolve('./hotModuleReplacement'))})(${JSON.stringify(options)});
       module.hot.dispose(cssReload);
       module.hot.accept(undefined, cssReload);
     }