Use new eslint package

.eslintrc.js

@@ -1,5 +1,3 @@
-const jsSdkEslintCfg = require('matrix-js-sdk/.eslintrc');
-
 module.exports = {
     parserOptions: {
         ecmaVersion: 8,
@@ -10,17 +8,15 @@ module.exports = {
         // we also have some browser code (ie. the preload script)
         browser: true,
     },
-    extends: ["eslint:recommended", "google"],
+    extends: ["matrix-org"],
-    rules: jsSdkEslintCfg.rules,
+    rules: {
+        // js-sdk uses a babel rule which we can't use because we
+        // don't use babel, so remove it & put the original back
+        "babel/no-invalid-this": "off",
+        "no-invalid-this": "error",
+        "quotes": "off",
+        "indent": "off",
+        "prefer-promise-reject-errors": "off",
+        "no-async-promise-executor": "off",
+    }
 }
-
-// js-sdk uses a babel rule which we can't use because we
-// don't use babel, so remove it & put the original back
-delete module.exports.rules["babel/no-invalid-this"];
-module.exports.rules["no-invalid-this"] = "error";
-
-// also override the line length to be consistent with
-// vector-web / react-sdk rather than js-sdk
-module.exports.rules["max-len"] = ["warn", {
-    code: 120,
-}];

package.json

@@ -42,8 +42,9 @@
     "electron-builder-squirrel-windows": "^22.7.0",
     "electron-devtools-installer": "^2.2.4",
     "electron-notarize": "^0.2.0",
-    "eslint": "^5.8.0",
+    "eslint": "7.3.1",
     "eslint-config-google": "^0.7.1",
+    "eslint-config-matrix-org": "^0.1.2",
     "eslint-plugin-babel": "^4.1.2",
     "find-npm-prefix": "^1.0.2",
     "fs-extra": "^8.1.0",