package/squid: update to 6.13

See here for changes:
https://github.com/squid-cache/squid/releases/tag/SQUID_6_11
https://github.com/squid-cache/squid/releases/tag/SQUID_6_12
https://github.com/squid-cache/squid/releases/tag/SQUID_6_13

Download URL moved to Github.

Signed-off-by: Waldemar Brodkorb <wbx@openadk.org>
[Peter: use SQUID_VERSION in _SITE as suggested by Baruch]
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/squid/squid.hash

@@ -1,6 +1,3 @@
-# From http://www.squid-cache.org/Versions/v6/squid-6.10.tar.xz.asc
-md5  86deefa7282c4388be95260aa4d4cf6a  squid-6.10.tar.xz
-sha1  70e90865df0e4e9ba7765b622da40bda9bb8fc5d  squid-6.10.tar.xz
 # Locally calculated
-sha256  0b07b187e723f04770dd25beb89aec12030a158696aa8892d87c8b26853408a7  squid-6.10.tar.xz
+sha256  232e0567946ccc0115653c3c18f01e83f2d9cc49c43d9dead8b319af0b35ad52  squid-6.13.tar.xz
 sha256  8177f97513213526df2cf6184d8ff986c675afb514d4e68a404010521b880643  COPYING

package/squid/squid.mk

@@ -4,9 +4,9 @@
 #
 ################################################################################
 
-SQUID_VERSION = 6.10
+SQUID_VERSION = 6.13
 SQUID_SOURCE = squid-$(SQUID_VERSION).tar.xz
-SQUID_SITE = http://www.squid-cache.org/Versions/v6
+SQUID_SITE = https://github.com/squid-cache/squid/releases/download/SQUID_$(subst .,_,$(SQUID_VERSION))
 SQUID_LICENSE = GPL-2.0+
 SQUID_LICENSE_FILES = COPYING
 SQUID_CPE_ID_VENDOR = squid-cache