Bundled Themes: Bump version numbers and update changelogs in default themes for WordPress 5.4.

Props ianbelanger, desrosj, SergeyBiryukov.
Fixes #49743.
Built from https://develop.svn.wordpress.org/trunk@47539


git-svn-id: http://core.svn.wordpress.org/trunk@47314 1a063a9b-81f0-0310-95a4-ce76da25c4cd

readme.txt

@@ -1,7 +1,7 @@
 === Twenty Twelve ===
 Contributors: wordpressdotorg
 Tested up to: 5.0
-Stable tag: 3.0
+Stable tag: 3.1
 License: GPLv2 or later
 License URI: http://www.gnu.org/licenses/gpl-2.0.html
 Tags: blog, one-column, two-columns, right-sidebar, custom-background, custom-header, custom-menu, editor-style, featured-images, flexible-header, footer-widgets, full-width-template, microformats, post-formats, rtl-language-support, sticky-post, theme-options, translation-ready
@@ -42,6 +42,11 @@ Source: https://github.com/aFarkas/html5shiv
 
 == Changelog ==
 
+= 3.1 =
+* Released: March 31, 2020
+
+https://codex.wordpress.org/Twenty_Twelve_Theme_Changelog#Version_3.1
+
 = 3.0 =
 * Released: May 7, 2019
 

style.css

@@ -4,7 +4,7 @@ Theme URI: https://wordpress.org/themes/twentytwelve/
 Author: the WordPress team
 Author URI: https://wordpress.org/
 Description: The 2012 theme for WordPress is a fully responsive theme that looks great on any device. Features include a front page template with its own widgets, an optional display font, styling for post formats on both index and single views, and an optional no-sidebar page template. Make it yours with a custom menu, header image, and background.
-Version: 3.0
+Version: 3.1
 Requires at least: 3.5
 Requires PHP: 5.2.4
 License: GNU General Public License v2 or later