CI: enable Dependabot Updates for NPM packages

The JS test suite uses the `jasmine` test framework from NPM;
this change enables Dependabot to let us know about updates for
it (and its dependencies).

Author: jayaddison

.github/dependabot.yml

@@ -12,6 +12,10 @@ updates:
     directory: "/"
     schedule:
       interval: "daily"
+  - package-ecosystem: "npm"
+    directory: "/"
+    schedule:
+      interval: "daily"
     groups:
       all-dependencies:
         patterns: