package/zsh: security bump to version 5.8.1

Fixes the following security issue:

- CVE-2021-45444: In zsh before 5.8.1, an attacker can achieve code
  execution if they control a command output inside the prompt, as
  demonstrated by a %F argument.  This occurs because of recursive
  PROMPT_SUBST expansion.

The 5.8.1 release is not listed in MD5SUM, so drop the md5 hash.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/zsh/zsh.hash

@@ -1,7 +1,3 @@
-# From http://www.zsh.org/pub/MD5SUM
-md5  e02a5428620b3dd268800c7843b3dd4d  zsh-5.8.tar.xz
-# Calculated based on the hash above and after checking signature
-# http://www.zsh.org/pub/zsh-5.8.tar.xz.asc
-sha256  dcc4b54cc5565670a65581760261c163d720991f0d06486da61f8d839b52de27  zsh-5.8.tar.xz
 # Locally calculated
+sha256  b6973520bace600b4779200269b1e5d79e5f505ac4952058c11ad5bbf0dd9919  zsh-5.8.1.tar.xz
 sha256  d06fdf3ef9b1ec69d6b9e170b0a9516fbad3523261ff1668bde3bfea6e0ef5f5  LICENCE

package/zsh/zsh.mk

@@ -4,7 +4,7 @@
 #
 ################################################################################
 
-ZSH_VERSION = 5.8
+ZSH_VERSION = 5.8.1
 ZSH_SITE = http://www.zsh.org/pub
 ZSH_SOURCE = zsh-$(ZSH_VERSION).tar.xz
 ZSH_DEPENDENCIES = ncurses