Build: replace grunt tasks with npm scripts

Includes:

- **lint**: lint all code using new eslint flat config
- **build**: build using rollup, minify using uglify, process for dist
- **npmcopy**: copy some node module files to the external folder
- **start**: watch source files and rebuild on changes using rollup.watch

Also:
- Update the build function in the release script to use the new build
- Update CONTRIBUTING.md and README.md with new scripts
- Confirm the min file was identical to the main branch build, aside from the version update.
- Keep uglify-js at 3.9.4, which is the last version that officially
  supported the ie8 argument, which we need for ie9
- update browserstack project name to jquery-migrate
- run browserstack at least once a week

Closes gh-512

Author: timmywil

.eslintignore

@@ -4,6 +4,9 @@ on:
   push:
     branches:
       - main
+  # Once a week every Tuesday
+  schedule:
+    - cron: "12 2 * * 2"
 
 jobs:
   test:
@@ -70,8 +73,8 @@ jobs:
       - name: Install dependencies
         run: npm install
 
-      - name: Build
-        run: npm run build
+      - name: Pretest script
+        run: npm run pretest
 
       - name: Test
         run: |

.eslintrc-browser.json

@@ -4,6 +4,9 @@ on:
   push:
     branches:
       - main
+  # Once a week every Tuesday
+  schedule:
+    - cron: "42 1 * * 2"
 
 jobs:
   test:
@@ -55,8 +58,8 @@ jobs:
       - name: Install dependencies
         run: npm install
 
-      - name: Build
-        run: npm run build
+      - name: Pretest script
+        run: npm run pretest
 
       - name: Test
         run: |

.eslintrc-node.json

@@ -8,11 +8,9 @@ CDN
 /*.html
 .DS_Store
 .sizecache.json
+.eslintcache
 
-# Ignore everything in dist folder except for eslint config
-/dist/*
-!/dist/.eslintrc.json
-
+/dist
 /external
 /node_modules
 

.eslintrc.json

@@ -68,11 +68,8 @@ See: [jQuery Core Style Guide](http://docs.jquery.com/JQuery_Core_Style_Guidelin
 
 To test the plugin you will need:
 
-* Some kind of localhost server(any will do)
 * Node.js
 * NPM (comes with the latest version of Node.js)
-* Grunt (install with: `npm install grunt -g`)
-
 
 ### Build a Local Copy of the plugin
 
@@ -108,13 +105,19 @@ Get in the habit of pulling in the "upstream" `main` branch to stay up to date a
 $ git pull upstream main
 ```
 
-Run the Grunt tools:
+Run the build and rebuild when source files change:
+
+```bash
+$ npm start
+```
+
+In another terminal, run the test server:
 
 ```bash
-$ grunt && grunt watch
+$ npm run test:server
 ```
 
-Now open the jQuery test suite in a browser at http://localhost/test. If there is a port, be sure to include it.
+Now open the jQuery test suite in a browser at http://localhost:3000/test/.
 
 Success! You just built and tested jQuery!
 

.github/workflows/browserstack-3.x.yml

@@ -89,21 +89,12 @@ Build and run tests:
 ====================================================
 
 ## Build with `npm` commands
-```sh
-$ git clone git://github.com/jquery/jquery-migrate.git
-$ cd jquery-migrate
-$ npm install
-$ npm run build
-```
-
-## Build with [`grunt`](http://gruntjs.com/)
 
 ```sh
 $ git clone git://github.com/jquery/jquery-migrate.git
 $ cd jquery-migrate
 $ npm install
-$ npm install -g grunt-cli
-$ grunt build
+$ npm run build
 ```
 
 ### Run tests
@@ -115,5 +106,7 @@ $ npm test
 ### Or
 
 ```sh
-$ grunt test
+$ npm run test:server
 ```
+
+and open http://localhost:3000/test/ in your browser.