chore: run lint action when NPM dependencies change (#1554)

Right now the lint GitHub Action only runs when lintable files (JS, MD, SCSS) are modified. This PR will also trigger the lint action when the package.json and/or package-lock.json files change so that we can better assess the impact of, say, a Dependabot update to Stylelint.

.github/workflows/lint.yml

@@ -3,12 +3,16 @@ name: Lint assets
 on:
   push:
     paths:
+      - 'package.json'
+      - 'package-lock.json'
       - '**.js'
       - '**.md'
       - '**.scss'
       - '!src/collections/**.md'
   pull_request:
     paths:
+      - 'package.json'
+      - 'package-lock.json'
       - '**.js'
       - '**.md'
       - '**.scss'