package/libkrb5: security bump to version 1.18.4

- Fix a denial of service attack against the KDC encrypted challenge
  code [CVE-2021-36222].
- Fix a memory leak when gss_inquire_cred() is called without a
  credential handle.
- Update indentation in hash file (two spaces)
- Update hash of NOTICE (update in year:
  https://github.com/krb5/krb5/commit/9cbfdf65e1718849cb03844d65930e5138e88195)

https://web.mit.edu/kerberos/krb5-1.18/krb5-1.18.4.html

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/libkrb5/libkrb5.hash

@@ -1,5 +1,5 @@
 # Locally calculated after checking pgp signature
-sha256	e61783c292b5efd9afb45c555a80dd267ac67eebabca42185362bee6c4fbd719  krb5-1.18.3.tar.gz
+sha256  66085e2f594751e77e82e0dbf7bbc344320fb48a9df2a633cfdd8f7d6da99fc8  krb5-1.18.4.tar.gz
 
 # Hash for license file:
-sha256	b7a5f14a8719bce5e49a761998aa55438fc890fb40f71228d6a49546f6d5690d  NOTICE
+sha256  7fba8b076bdc2cfef1d0813c5d4067d76d5be60c32d84de22d5d1cf451744feb  NOTICE

package/libkrb5/libkrb5.mk

@@ -5,7 +5,7 @@
 ################################################################################
 
 LIBKRB5_VERSION_MAJOR = 1.18
-LIBKRB5_VERSION = $(LIBKRB5_VERSION_MAJOR).3
+LIBKRB5_VERSION = $(LIBKRB5_VERSION_MAJOR).4
 LIBKRB5_SITE = https://web.mit.edu/kerberos/dist/krb5/$(LIBKRB5_VERSION_MAJOR)
 LIBKRB5_SOURCE = krb5-$(LIBKRB5_VERSION).tar.gz
 LIBKRB5_SUBDIR = src