package/libkrb5: security bump to version 1.18.3

Fixes the following security issues:

- CVE-2020-28196: MIT Kerberos 5 (aka krb5) before 1.17.2 and 1.18.x before
  1.18.3 allows unbounded recursion via an ASN.1-encoded Kerberos message
  because the lib/krb5/asn.1/asn1_encode.c support for BER indefinite
  lengths lacks a recursion limit.

Also fix .hash file indentation.

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

package/libkrb5/libkrb5.hash

@@ -1,5 +1,5 @@
 # Locally calculated after checking pgp signature
-sha256	02a4e700f10936f937cd1a4c303cab8687a11abecc6107bd4b706b9329cd5400	krb5-1.18.1.tar.gz
+sha256	e61783c292b5efd9afb45c555a80dd267ac67eebabca42185362bee6c4fbd719  krb5-1.18.3.tar.gz
 
 # Hash for license file:
-sha256	b7a5f14a8719bce5e49a761998aa55438fc890fb40f71228d6a49546f6d5690d	NOTICE
+sha256	b7a5f14a8719bce5e49a761998aa55438fc890fb40f71228d6a49546f6d5690d  NOTICE

package/libkrb5/libkrb5.mk

@@ -5,7 +5,7 @@
 ################################################################################
 
 LIBKRB5_VERSION_MAJOR = 1.18
-LIBKRB5_VERSION = $(LIBKRB5_VERSION_MAJOR).1
+LIBKRB5_VERSION = $(LIBKRB5_VERSION_MAJOR).3
 LIBKRB5_SITE = https://web.mit.edu/kerberos/dist/krb5/$(LIBKRB5_VERSION_MAJOR)
 LIBKRB5_SOURCE = krb5-$(LIBKRB5_VERSION).tar.gz
 LIBKRB5_SUBDIR = src