- enable patch mozilla-bmo1896958.patch for Leap 15.5
https://bugzilla.opensuse.org/show_bug.cgi?id=1230257

- request inclusion in Leap 15.5 and 15.6:
https://bugzilla.opensuse.org/show_bug.cgi?id=1230257

- update to SeaMonkey 2.53.19
* Cancel button in SeaMonkey bookmarking star ui not working bug
1872623.
* Remove OfflineAppCacheHelper.jsm copy from SeaMonkey and use the
one in toolkit bug 1896292.
* Remove obsolete registerFactoryLocation calls from cZ bug 1870930.
* Remove needless implements='nsIDOMEventListener' and QI bug
1611010.
* Replace use of nsIStandardURL::Init bug 1864355.
* Switch SeaMonkey website from hg.mozilla.org to heptapod. bug
1870934.
* Allow view-image to open a data: URI by setting a flag on the
loadinfo bug 1877001.
* Save-link-as feature should use the loading principal and context
menu using nsIContentPolicy.TYPE_SAVE_AS_DOWNLOAD bug 1879726.
* Use punycode in SeaMonkey JS bug 1864287.
* Font lists in preferences are no longer grouped by font type, port
asynchronous handling like Bug 1399206 bug 1437393.
* SeaMonkey broken tab after undo closed tab with invalid protocol
bug 1885748.
* SeaMonkey session restore is missing the checkboxes in the Classic
theme bug 1896174.
* Implement about:credits on seamonkey-project.org website bug
1898467.
* Fix for the 0.0.0.0 day vulnerability oligo summary.