imagemagick: security bump to version 7.0.3-3

Fixes:
memory allocate failure in AcquireQuantumPixels (quantum.c)
heap-based buffer overflow in IsPixelMonochrome (pixel-accessor.h)

No CVEs assigned yet.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/imagemagick/imagemagick.hash

@@ -1,2 +1,2 @@
 # From http://www.imagemagick.org/download/releases/digest.rdf
-sha256 22df4f197985f36f77b7b0d44de92ff44415885045f0191b3319540bdc82ff53 ImageMagick-7.0.2-9.tar.xz
+sha256 6ed0b059c9a108a631e0febcf9a9338342e25df4bbc9a9531ffe36d66031b0d8 ImageMagick-7.0.3-3.tar.xz

package/imagemagick/imagemagick.mk

@@ -4,7 +4,7 @@
 #
 ################################################################################
 
-IMAGEMAGICK_VERSION = 7.0.2-9
+IMAGEMAGICK_VERSION = 7.0.3-3
 IMAGEMAGICK_SOURCE = ImageMagick-$(IMAGEMAGICK_VERSION).tar.xz
 IMAGEMAGICK_SITE = http://www.imagemagick.org/download/releases
 IMAGEMAGICK_LICENSE = Apache-2.0