Removed gulp premerge task (#2357)

.travis.yml

@@ -13,9 +13,12 @@ before_install:
 install:
 - npm ci
 before_script:
-- npm install -g gulp
-- gulp
-- gulp premerge
+# Rebuild Prism
+- npx gulp
+# Detect changes
+# First, we stage all changes and then detect if there is anything staged
+- git add --all && git diff-index --cached HEAD --stat --exit-code ||
+  (echo && echo "The above files changed because the build is not up to date." && echo "Please rebuild Prism." && exit 1)
 script: npm test
 deploy:
   provider: npm

gulpfile.js/index.js

@@ -12,7 +12,6 @@ const util = require('util');
 const fs = require('fs');
 
 const paths = require('./paths');
-const { premerge } = require('./premerge');
 const { changes, linkify } = require('./changelog');
 
 
@@ -216,7 +215,6 @@ const plugins = series(languagePlugins, minifyPlugins);
 module.exports = {
 	watch: watchComponentsAndPlugins,
 	default: parallel(components, plugins, componentsJsonToJs, build),
-	premerge,
 	linkify,
 	changes
 };