Release automation (#1720)

* Create autoamtic release script.

* Add changelog update date script.

* Improve release scripts.

* Apply suggestions from code review

Co-Authored-By: nventuro <nicolas.venturo@gmail.com>

* Apply suggestions from code review

Co-Authored-By: nventuro <nicolas.venturo@gmail.com>

* Remove moment dependency.

scripts/release/update-changelog-release-date.js

@@ -0,0 +1,33 @@
+#!/usr/bin/env node
+
+// Sets the release date of the current release in the changelog.
+// This is run automatically when npm version is run.
+
+const fs = require('fs');
+const cp = require('child_process');
+const moment = require('moment');
+
+const pkg = require('../../package.json');
+if (pkg.version.indexOf('-rc') !== -1) {
+  process.exit(0);
+}
+
+const version = pkg.version.replace(/-.*/, ''); // Remove the rc suffix
+
+const changelog = fs.readFileSync('CHANGELOG.md', 'utf8');
+
+// The changelog entry to be updated looks like this:
+// ## 2.5.3 (unreleased)
+// We need to add the date in a YYYY-MM-DD format, so that it looks like this:
+// ## 2.5.3 (2019-04-25)
+
+if (changelog.indexOf(`## ${version} (unreleased)`) === -1) {
+  throw Error(`Found no changelog entry for version ${version}`);
+}
+
+fs.writeFileSync('CHANGELOG.md', changelog.replace(
+  `## ${version} (unreleased)`,
+  `## ${version} (${new Date().toISOString().split('T')[0]})`)
+);
+
+cp.execSync('git add CHANGELOG.md', { stdio: 'inherit' });