General: Bump the recommended MySQL and MariaDB versions in `readme.html`.

* MySQL 5.6 has reached EOL (“End of Life”) in February 2021. The recommended minimum is bumped to 5.7 for now.
* MariaDB 10.1 has reached EOL in October 2020. The recommended minimum is bumped to 10.2 for now.

Follow-up to [31291], [35759], [52319], [52358], [meta11407].

Props JavierCasares, SergeyBiryukov.
See #41490, #meta5999.
Built from https://develop.svn.wordpress.org/trunk@52420


git-svn-id: http://core.svn.wordpress.org/trunk@52012 1a063a9b-81f0-0310-95a4-ce76da25c4cd

readme.html

@@ -58,7 +58,7 @@
 <h3>Recommendations</h3>
 <ul>
 	<li><a href="https://secure.php.net/">PHP</a> version <strong>7.4</strong> or greater.</li>
-	<li><a href="https://www.mysql.com/">MySQL</a> version <strong>5.6</strong> or greater OR <a href="https://mariadb.org/">MariaDB</a> version <strong>10.1</strong> or greater.</li>
+	<li><a href="https://www.mysql.com/">MySQL</a> version <strong>5.7</strong> or greater OR <a href="https://mariadb.org/">MariaDB</a> version <strong>10.2</strong> or greater.</li>
 	<li>The <a href="https://httpd.apache.org/docs/2.2/mod/mod_rewrite.html">mod_rewrite</a> Apache module.</li>
 	<li><a href="https://wordpress.org/news/2016/12/moving-toward-ssl/">HTTPS</a> support.</li>
 	<li>A link to <a href="https://wordpress.org/">wordpress.org</a> on your site.</li>

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.9-beta4-52419';
+$wp_version = '5.9-beta4-52420';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.