panels 8.x-4.5

This is an incremental update to Panels, which includes various bug releases.

This is the last version of Panels to support Drupal 8.5, 8.6, and 8.7

Changes since 8.x-4.4:

• Issue #3030976 by phenaproxima, bendeguz.csirmaz, colincalnan: Panels should check if there is an icon map before setting the no preview icon
• Issue #3114373 by phenaproxima: Require jQuery UI shim modules
• Issue #3109899 follow-up by phenaproxima, tim.plunkett: Declare compatibility with Drupal 9
• Issue #3109899 by phenaproxima, tim.plunkett: Declare compatibility with Drupal 9
• Issue #3070866 by Mohammad Fayoumi, joseph.olstad: Drupal 9 replace deprecated function drupal_set_message()
• Issue #3107784 by phenaproxima: Convert tests to PHPUnit
• Issue #3107809 by phenaproxima, tim.plunkett: Make tests run on Drupal core 8.8 and later
• Issue #2769801 by lamp5, DamienMcKenna, tobiberlin, joelpittet, benjy, sylus, Sinan Erdem, millionleaves, manuel.adan: Enable token browser for the page variant title field
• Issue #3045578 by tengoku: Bug Report: ( ! ) Warning: array_unique() expects parameter 1 to be array, string in Attributes.php on line 66