Add release build script and dependabot config

.github/dependabot.yml

@@ -0,0 +1,8 @@
+version: 2
+updates:
+  - package-ecosystem: npm
+    directory: /
+    schedule:
+      interval: daily
+    labels:
+      - dependencies

CONTRIBUTING.md

@@ -55,10 +55,11 @@ You can find the documentation for all this on the following locations:
 Building the extension is relatively easy through [Node.js](https://nodejs.org/en/). We use [Rollup](https://www.rollupjs.org/) to bundle the extension's Javascript code and manually copy over assets including images and the `manifest.json` file via [rollup-plugin-copy](https://www.npmjs.com/package/rollup-plugin-copy). Additionally, some browser-specific processing is applied to the manifest to work around some browser-specific incompatibilities. Build output goes to `build/chrome` and `build/firefox`.
 
 ```sh
-$ npm install          # Install dependencies
-$ npm run build        # Build extension
-$ npm run build:watch  # Automatically rebuild on file changes
-$ npm run docs         # Build documentation of internal interfaces
+$ npm install           # Install dependencies
+$ npm run build         # Build extension
+$ npm run build:watch   # Automatically rebuild on file changes
+$ npm run build:release # Install dependencies and perform a release build
+$ npm run docs          # Build documentation of internal interfaces
 ```
 
 Once you've built the extension, you can load it up in your browser for testing:

package.json

@@ -6,6 +6,7 @@
     "scripts": {
         "build": "rollup -c rollup.config.js",
         "build:watch": "rollup -c rollup.config.js --watch",
+        "build:release": "npm ci && cross-env NODE_ENV=production rollup -c rollup.config.js",
         "eslint": "eslint . --config .eslintrc.json --ignore-path .eslintignore",
         "docs": "jsdoc -c jsdoc.json"
     },