Security update for webkit2gtk3

Open Source Vulnerabilities openSUSE-SU-2020:0278-1

This update for webkit2gtk3 to version 2.26.4 fixes the following issues: Security issues fixed: - CVE-2019-8835: Fixed multiple memory corruption issues (bsc#1161719). - CVE-2019-8844: Fixed multiple memory corruption issues (bsc#1161719). - CVE-2019-8846: Fixed a use-after-free issue (bsc#1161719). - CVE-2020-3862: Fixed a memory handling issue (bsc#1163809). - CVE-2020-3864: Fixed a logic issue in the DOM object context handling (bsc#1163809). - CVE-2020-3865: Fixed a logic issue in the DOM object context handling (bsc#1163809). - CVE-2020-3867: Fixed an XSS issue (bsc#1163809). - CVE-2020-3868: Fixed multiple memory corruption issues that could have lead to arbitrary code execution (bsc#1163809). Non-security issues fixed: - Fixed issues while trying to play a video on NextCloud. - Fixed vertical alignment of text containing arabic diacritics. - Fixed build with icu 65.1. - Fixed page loading errors with websites using HSTS. - Fixed web process crash when displaying a KaTeX formula. - Fixed several crashes and rendering issues. - Switched to a single web process for Evolution and geary (bsc#1159329 glgo#GNOME/evolution#587). This update was imported from the SUSE:SLE-15:Update update project.