fix(svn): use correct HTTPS URL for SVN check

Same fix as PR Zodiac1978#81 — the old http://svn.wp-plugins.org
URL is broken, causing closed plugins to show as
"Not found" instead of "Closed".

Author: apermo

rt-plugin-report.php

@@ -420,7 +420,7 @@ private function assemble_plugin_report( $slug ) {
 		 */
 		private function check_exists_in_svn( $slug ) {
 			// Attempt to load the plugin's SVN repo page.
-			$response = wp_remote_get( 'http://svn.wp-plugins.org/' . $slug . '/' );
+			$response = wp_remote_get( 'https://plugins.svn.wordpress.org/' . rawurlencode( $slug ) . '/' );
 			// If the return value was a WP_Error, assume the answer is no.
 			if ( is_wp_error( $response ) ) {
 				return false;