chore: update devDependencies and address security vulnerabilities

- Upgrade gulp to v5 and update various gulp plugins (bump, git, mocha, etc.).
- Update mocha and karma to latest stable versions.
- Resolve ESLint peer dependency conflict by aligning eslint-plugin-angular.
- Fix linting error in examples/app.js (missing curly braces).

Author: jtblin

examples/app.js

@@ -22,7 +22,9 @@
 
   app.filter('slug', () => {
     return (input) => {
-      if (!input) return '';
+      if (!input) {
+        return '';
+      }
       return input.toLowerCase().replace(/ /g, '-');
     };
   });