superseding the 91.0 version as another security and hotfix release

- Mozilla Firefox 91.0.1
* Fixed an issue causing buttons on the tab bar to be resized when
loading certain websites (bmo#1704404)
* Fixed an issue which caused tabs from private windows to be
visible in non-private windows when viewing switch-to-tab results
in the address bar panel (bmo#1720369)
* Various stability fixes
MFSA 2021-37 (bsc#1189547)
* CVE-2021-29991 (bmo#1724896)
Header Splitting possible with HTTP/3 Responses

- Mozilla Firefox 91.0
MFSA 2021-33 (bsc#1188891)
* CVE-2021-29986 (bmo#1696138)
Race condition when resolving DNS names could have led to
memory corruption
* CVE-2021-29981 (bmo#1707774)
Live range splitting could have led to conflicting
assignments in the JIT
* CVE-2021-29988 (bmo#1717922)
Memory corruption as a result of incorrect style treatment
* CVE-2021-29983 (bmo#1719088)
Firefox for Android could get stuck in fullscreen mode
* CVE-2021-29984 (bmo#1720031)
Incorrect instruction reordering during JIT optimization
* CVE-2021-29980 (bmo#1722204)
Uninitialized memory in a canvas object could have led to
memory corruption
* CVE-2021-29987 (bmo#1716129)
Users could have been tricked into accepting unwanted