Fix reference to js-sdk lint config

.eslintrc.js

@@ -5,7 +5,10 @@ const path = require('path');
 // but only if they come from a module that starts with eslint-config-
 // So we load the filename directly (and it could be in node_modules/
 // or or ../node_modules/ etc)
-const matrixJsSdkPath = path.dirname(require.resolve('matrix-js-sdk'));
+//
+// We add a `..` to the end because the js-sdk lives out of lib/, but the eslint
+// config is at the project root.
+const matrixJsSdkPath = path.join(path.dirname(require.resolve('matrix-js-sdk')), '..');
 
 module.exports = {
     parser: "babel-eslint",