Merge pull request #709 from Polymer/release

Release lit-element 2.2.0

Author: aomarks

CHANGELOG.md

@@ -9,14 +9,17 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
    PRs should document their user-visible changes (if any) in the
    Unreleased section, uncommenting the header as necessary.
 -->
-### Added
-* css tagged template literals now allow numbers to be used in expressions ([#488](https://github.com/Polymer/lit-element/issues/488)).
 
+<!-- ## Unreleased -->
+<!-- ### Added -->
 <!-- ### Changed -->
 <!-- ### Removed -->
 <!-- ### Fixed -->
 
-## Unreleased
+
+## [2.2.0] - 2019-06-11
+### Added
+* css tagged template literals now allow numbers to be used in expressions ([#488](https://github.com/Polymer/lit-element/issues/488)).
 
 ## [2.1.0] - 2019-03-21
 ### Changed

check-version-tracker.js

@@ -0,0 +1,26 @@
+/**
+ * @license
+ * Copyright (c) 2019 The Polymer Project Authors. All rights reserved.
+ * This code may only be used under the BSD style license found at
+ * http://polymer.github.io/LICENSE.txt
+ * The complete set of authors may be found at
+ * http://polymer.github.io/AUTHORS.txt
+ * The complete set of contributors may be found at
+ * http://polymer.github.io/CONTRIBUTORS.txt
+ * Code distributed by Google as part of the polymer project is also
+ * subject to an additional IP rights grant found at
+ * http://polymer.github.io/PATENTS.txt
+ */
+
+const fs = require('fs');
+const path = require('path');
+
+const version = require(path.join(__dirname, 'package.json')).version;
+const ts = fs.readFileSync(path.join(__dirname, 'src', 'lit-element.ts'));
+if (!ts.includes(version)) {
+  console.log(
+      `\nExpected lit-element.ts to contain current version "${version}"`);
+  console.log(
+      `Don't forget to update the version tracker string before release!`);
+  process.exit(1);
+}