main/mkinitfs: upgrade to 2.1.3

fixes #477

main/mkinitfs/0001-inlude-ld64-uClibc-in-initramfs-image.patch

-From e282075798a15081a5aca8d8a5ad8c5ffe406cc2 Mon Sep 17 00:00:00 2001
-From: Natanael Copa <ncopa@alpinelinux.org>
-Date: Thu, 25 Nov 2010 15:32:48 +0000
-Subject: [PATCH] inlude ld64-uClibc in initramfs image
-
----
- files.d/base |    4 ++--
- 1 files changed, 2 insertions(+), 2 deletions(-)
-
-diff --git a/files.d/base b/files.d/base
-index 965b67c..06bb3d8 100644
---- a/files.d/base
-+++ b/files.d/base
-@@ -10,8 +10,8 @@
- /lib/libuClibc-[0-9]*
- /lib/libc.so.*
- /lib/libz.*
--/lib/ld-uClibc-[0-9]*
--/lib/ld-uClibc.so*
-+/lib/ld*-uClibc-[0-9]*
-+/lib/ld*-uClibc.so*
- /lib/mdev
- /sbin/apk
- /etc/modprobe.d/blacklist
--- 
-1.7.3.2
-