build: update build tools

Author: mrholek

.browserslistrc

@@ -0,0 +1,11 @@
+# https://github.com/browserslist/browserslist#readme
+
+>= 0.5%
+last 2 major versions
+not dead
+Chrome >= 60
+Firefox >= 60
+Firefox ESR
+iOS >= 12
+Safari >= 12
+not Explorer <= 11

.eslintrc

@@ -0,0 +1,25 @@
+module.exports = {
+  // parser: '@typescript-eslint/parser', // Specifies the ESLint parser
+  parserOptions: {
+    ecmaVersion: 2020, // Allows for the parsing of modern ECMAScript features
+    sourceType: 'module', // Allows for the use of imports
+    ecmaFeatures: {
+      jsx: true, // Allows for the parsing of JSX
+    },
+  },
+  settings: {
+    react: {
+      version: 'detect', // Tells eslint-plugin-react to automatically detect the version of React to use
+    },
+  },
+  extends: [
+    'react-app',
+    'plugin:react/recommended', // Uses the recommended rules from @eslint-plugin-react
+    'plugin:prettier/recommended', // Enables eslint-plugin-prettier and eslint-config-prettier. This will display prettier errors as ESLint errors. Make sure this is always the last configuration in the extends array.
+  ],
+  plugins: ['react', 'react-hooks'],
+  rules: {
+    // Place to specify ESLint rules. Can be used to overwrite rules specified from the extended configs
+    // e.g. "@typescript-eslint/explicit-function-return-type": "off",
+  },
+}

.eslintrc.js

@@ -35,7 +35,6 @@
     "classnames": "^2.3.1",
     "core-js": "^3.10.1",
     "enzyme": "^3.11.0",
-    "node-sass": "^5.0.0",
     "prop-types": "^15.7.2",
     "react": "^17.0.2",
     "react-app-polyfill": "^2.0.0",
@@ -46,14 +45,17 @@
   },
   "devDependencies": {
     "auto-changelog": "~2.2.1",
+    "eslint": "^7.27.0",
+    "eslint-config-prettier": "^8.3.0",
     "eslint-plugin-prettier": "^3.3.1",
-    "gatsby-plugin-sitemap": "^3.3.0",
+    "node-sass": "^5.0.0",
     "prettier": "2.2.1",
     "react-scripts": "^4.0.3"
   },
   "scripts": {
     "start": "react-scripts start",
     "build": "react-scripts build",
+    "lint": "eslint 'src/**/*.js'",
     "test": "react-scripts test",
     "test:cov": "npm test -- --coverage --watchAll=false",
     "test:debug": "react-scripts --inspect-brk test --runInBand",
@@ -63,15 +65,6 @@
   "bugs": {
     "url": "https://github.com/coreui/coreui-free-react-admin-template/issues"
   },
-  "eslintConfig": {
-    "extends": "react-app"
-  },
-  "browserslist": [
-    ">0.2%",
-    "not dead",
-    "not ie <= 10",
-    "not op_mini all"
-  ],
   "jest": {
     "collectCoverageFrom": [
       "src/**/*.{js,jsx}",