chore: add eslint

Author: lindsaylevine

.editorconfig

@@ -0,0 +1,10 @@
+root = true
+
+[*]
+indent_style = space
+indent_size = 2
+end_of_line = lf
+charset = utf-8
+max_line_length = 120
+trim_trailing_whitespace = true
+insert_final_newline = true

.eslintrc.js

@@ -0,0 +1,7 @@
+const { overrides } = require('@netlify/eslint-config-node')
+
+module.exports = {
+  extends: '@netlify/eslint-config-node',
+  rules: {},
+  overrides: [...overrides],
+}

.gitattributes

@@ -0,0 +1 @@
+* text=auto eol=lf

.github/workflows/test.yml

@@ -26,5 +26,8 @@ jobs:
         uses: actions/setup-node@v2
         with:
           node-version: ${{ matrix.node-version }}
+      - name: Linting
+        run: npm run format:ci
+        if: "${{ matrix.node-version == '15.x' }}"
       - run: npm install
       - run: npm test

package.json

@@ -11,8 +11,15 @@
     "!src/tests"
   ],
   "scripts": {
-    "format": "prettier --write .",
     "build": "next build test/sample",
+    "format": "run-s format:check-fix:*",
+    "format:ci": "run-s format:check:*",
+    "format:check-fix:lint": "run-e format:check:lint format:fix:lint",
+    "format:check:lint": "cross-env-shell eslint $npm_package_config_eslint",
+    "format:fix:lint": "cross-env-shell eslint --fix $npm_package_config_eslint",
+    "format:check-fix:prettier": "run-e format:check:prettier format:fix:prettier",
+    "format:check:prettier": "cross-env-shell prettier --check $npm_package_config_prettier",
+    "format:fix:prettier": "cross-env-shell prettier --write $npm_package_config_prettier",
     "test:plugin": "npm run build && jest",
     "test:src": "jest --config src/tests/jest.config.js",
     "test": "npm run test:plugin && npm run test:src",
@@ -26,6 +33,10 @@
     "prepublishOnly:install": "npm ci",
     "prepublishOnly:test": "npm test"
   },
+  "config": {
+    "eslint": "--ignore-path .gitignore --cache --format=codeframe --max-warnings=0 \"{src,scripts,tests,.github}/**/*.{js,md,html}\" \"*.{js,md,html}\" \".*.{js,md,html}\"",
+    "prettier": "--ignore-path .gitignore --loglevel=warn \"{src,scripts,tests,.github}/**/*.{js,md,yml,json,html}\" \"*.{js,yml,json,html}\" \".*.{js,yml,json,html}\" \"!package-lock.json\""
+  },
   "repository": {
     "type": "git",
     "url": "git+https://github.com/netlify/netlify-plugin-nextjs.git"
@@ -77,7 +88,7 @@
   "husky": {
     "hooks": {
       "commit-msg": "commitlint -E HUSKY_GIT_PARAMS",
-      "pre-commit": "prettier --check ."
+      "pre-push": "npm run format"
     }
   },
   "engines": {