vendor/libarchive: upgrade from 3.3.3 to 3.4.3

vendor/libarchive: upgrade from 3.3.3 to 3.4.3

Fixes CVE-2019-18408.

New features:
- support for pzstd compressed files
- support for RHT.security.selinux tar extended attribute
- atomic file extraction support (bsdtar -x --safe-writes)
- unicode filename support for reading lha/lzh archives
- new pax write option "xattrhdr"
- read support for RAR 5.0 archives
- read support for ZIPX archives with xz, lzma, ppmd8 and bzip2
  compression
- support for non-recursive list and extract
- new tar option: --exclude-vcs
- 64-bit ar format support

Bugfixes:
- use-after-free in a certain ARCHIVE_FAILED situation
- various zstd fixes and improvements
- child process handling fixes
- compression buffer fix in XAR writer
- fix for uname and gname longer than 32 characters in PAX writer
- fix segfault when archiving hard links in ISO9660 and XAR writers
- fix support for extracting 7z archive entries with Delta filter
- security fixes and optimizations to write filter logic
- security fix related to use of readlink(2)
- sparse file handling fixes
- fix reading Android APK archives
- fix problems related to unreadable directories
- patches from OpenBSD to libarchive_fe/passphrase.c
- support extracting ACLs with in-entry comments
- support extracting extattrs as non-root on non-user-writable files
- various resource leak, use-after-free and crash fixes

For details, see release notes or commit history on github:
https://github.com/libarchive/libarchive/wiki/ReleaseNotes