Fixed plugin version notice

CHANGELOG.md

+## [3.2.1] - 2019-11-15
+### Fixed
+- Fixed plugin version notice
+
 ## [3.2.0] - 2019-11-14
 ### Added
 - Minimum required plugin version notice

src/Basic_Requirement_Checker_Factory.php

@@ -49,7 +49,8 @@
 
 			if ( isset( $requirements['plugins'] ) ) {
 				foreach ( $requirements['plugins'] as $requirement ) {
-					$requirements_checker->add_plugin_require( $requirement['name'], $requirement['nice_name'], $requirement['version'] );
+					$version = isset( $requirement['version'] ) ? $requirement['version'] : null;
+					$requirements_checker->add_plugin_require( $requirement['name'], $requirement['nice_name'], $version );
 				}
 
 				$requirements_checker->transient_delete_on_plugin_version_changed();