Update vendor/libarchive/dist to git 31c0a517c91f44eeee717a04db8b075cadda83d8

Update vendor/libarchive/dist to git 31c0a517c91f44eeee717a04db8b075cadda83d8

Relevant vendor changes:
  PR #1085: Fix a null pointer dereference bug in zip writer
  PR #1110: ZIP reader added support for XZ, LZMA, PPMD8 and BZIP2
            decopmpression
  PR #1116: Add support for 64-bit ar format
  PR #1120: Fix a 7zip crash [1] and a ISO9660 infinite loop [2]
  PR #1125: RAR5 reader - fix an invalid read and a memory leak
  PR #1131: POSIX reader - do not fail when tree_current_lstat() fails
            due to ENOENT [3]
  PR #1134: Delete unnecessary null pointer checks before calls of free()
  OSS-Fuzz 10843: Force intermediate to uint64_t to make UBSAN happy.
  OSS-Fuzz 11011: Avoid buffer overflow in rar5 reader

PR:		233006 [3]
Security:	CVE-2019-1000019 [1], CVE-2019-1000020 [2]