Release Zulip Server 2.1.6.

This bug broke the 2.1.5 release on Ubuntu Xenial.

docs/overview/changelog.md

@@ -7,6 +7,11 @@ All notable changes to the Zulip server are documented in this file.
 This section lists notable unreleased changes; it is generally updated
 in bursts.
 
+### 2.1.6 -- 2020-06-17
+
+- Fixed use of Python 3.6+ syntax in 2.1.5 release that prevented
+  installation on Ubuntu Xenial.
+
 ### 2.1.5 -- 2020-06-16
 
 - CVE-2020-12759: Fix reflected XSS vulnerability in Dropbox webhook.

version.py

@@ -1,6 +1,6 @@
 import os
 
-ZULIP_VERSION = "2.1.5"
+ZULIP_VERSION = "2.1.6"
 # Add information on number of commits and commit hash to version, if available
 zulip_git_version_file = os.path.join(os.path.dirname(os.path.abspath(__file__)), 'zulip-git-version')
 if os.path.exists(zulip_git_version_file):
@@ -10,7 +10,7 @@ if os.path.exists(zulip_git_version_file):
             ZULIP_VERSION = version
 
 LATEST_MAJOR_VERSION = "2.1"
-LATEST_RELEASE_VERSION = "2.1.5"
+LATEST_RELEASE_VERSION = "2.1.6"
 LATEST_RELEASE_ANNOUNCEMENT = "https://blog.zulip.org/2019/12/13/zulip-2-1-released/"
 
 # Versions of the desktop app below DESKTOP_MINIMUM_VERSION will be

zerver/views/auth.py

@@ -618,9 +618,8 @@ class TwoFactorLoginView(BaseTwoFactorLoginView):
             return super().done(form_list, **kwargs)
 
 @has_request_variables
-def login_page(
-    request: HttpRequest, next: str = REQ(default="/"), **kwargs: Any,
-) -> HttpResponse:
+def login_page(request: HttpRequest,
+               next: str = REQ(default="/"), **kwargs: Any) -> HttpResponse:
     # To support previewing the Zulip login pages, we have a special option
     # that disables the default behavior of redirecting logged-in users to the
     # logged-in app.