Include the .pcss extension for PostCSS files

Author: Oliver Davies

lib/config-generator.js

@@ -245,6 +245,7 @@ class ConfigGenerator {
         // files.
         const cssExtensions = ['css'];
         if (this.webpackConfig.usePostCssLoader) {
+            cssExtensions.push('pcss');
             cssExtensions.push('postcss');
         }
 

test/config-generator.js

@@ -1340,7 +1340,7 @@ describe('The config-generator function', () => {
                 findRule(/\.(css)$/, actualConfig.module.rules);
             }).not.to.throw();
             expect(function() {
-                findRule(/\.(css|postcss)$/, actualConfig.module.rules);
+                findRule(/\.(css|pcss|postcss)$/, actualConfig.module.rules);
             }).to.throw();
         });
 
@@ -1358,7 +1358,7 @@ describe('The config-generator function', () => {
                 findRule(/\.(css)$/, actualConfig.module.rules);
             }).to.throw();
             expect(function() {
-                findRule(/\.(css|postcss)$/, actualConfig.module.rules);
+                findRule(/\.(css|pcss|postcss)$/, actualConfig.module.rules);
             }).to.not.throw();
         });
     });