meta: check for formatting in CI

.github/workflows/linters.yml

@@ -45,6 +45,8 @@ jobs:
         run: corepack yarn workspaces focus @uppy/angular @uppy-example/angular @uppy-example/react-native-expo @uppy/react-native @uppy-dev/build
       - name: Run linter
         run: corepack yarn run lint
+      - name: Run Prettier
+        run: corepack yarn run format:check-diff
 
   lint_md:
     name: Lint Markdown

package.json

@@ -134,6 +134,10 @@
     "lint:css": "stylelint ./packages/**/*.scss",
     "lint:css:fix": "stylelint ./packages/**/*.scss --fix",
     "lint": "eslint . --cache",
+    "format:show-diff": "git diff --quiet || (echo 'Unable to show a diff because there are unstaged changes'; false) && (prettier . -w --loglevel silent && git --no-pager diff; git restore .)",
+    "format:check": "prettier -c .",
+    "format:check-diff": "yarn format:check || (yarn format:show-diff && false)",
+    "format": "prettier -w .",
     "release": "PACKAGES=$(yarn workspaces list --json) yarn workspace @uppy-dev/release interactive",
     "size": "echo 'JS Bundle mingz:' && cat ./packages/uppy/dist/uppy.min.js | gzip | wc -c && echo 'CSS Bundle mingz:' && cat ./packages/uppy/dist/uppy.min.css | gzip | wc -c",
     "e2e": "yarn build && yarn e2e:skip-build",