get eslint working again

.eslintignore

···
 node_modules
 coverage
+demo

.eslintrc

···
     "no-param-reassign": "off",
     "react/forbid-prop-types": "off",
     "react/jsx-boolean-value": ["error", "always"],
+    "react/jsx-filename-extension": "off",
     "react/jsx-no-bind": "off",
     "react/no-unused-prop-types": "off", // re-enable, there's a bug in eslint that leads to false-positives
     "react/require-default-props": "off",

package.json

···
     "build:css": "postcss src/styles.css --use autoprefixer -d dist/ --no-map",
     "build:js": "cross-env NODE_ENV=production rollup -c",
     "clean": "rimraf dist",
-    "lint": "eslint --ext .js,.jsx --cache . && echo \"eslint: no lint errors found\" || true",
+    "lint": "eslint src",
     "prepublish": "npm run clean && npm run build",
     "test": "jest --config jest.config.js --coverage",
     "start": "npm-run-all --parallel start:js start:css",