libcurl: security bump to version 7.56.1

Fixes CVE-2017-1000257 - IMAP FETCH response out of bounds read

https://curl.haxx.se/docs/adv_20171023.html

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
(cherry picked from commit 62d4dd2999a0446c2b868a7c6fbcc764a470493d)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/libcurl/libcurl.hash

@@ -1,4 +1,4 @@
 # Locally calculated after checking pgp signature
-# https://curl.haxx.se/download/curl-7.56.0.tar.xz.asc
-sha256 32437bcca0e9434384329fdc733547879d25ba70335b3cf9e3d9cbc3e71fd172  curl-7.56.0.tar.xz
+# https://curl.haxx.se/download/curl-7.56.1.tar.xz.asc
+sha256 8eed282cf3a0158d567a0feaa3c4619e8e847970597b5a2c81879e8f0d1a39d1  curl-7.56.1.tar.xz
 sha256 cbcf511f5702f7baf5424193a792bc9c18fab22bcbec2e6a587598389dc632c2  COPYING

package/libcurl/libcurl.mk

@@ -4,7 +4,7 @@
 #
 ################################################################################
 
-LIBCURL_VERSION = 7.56.0
+LIBCURL_VERSION = 7.56.1
 LIBCURL_SOURCE = curl-$(LIBCURL_VERSION).tar.xz
 LIBCURL_SITE = https://curl.haxx.se/download
 LIBCURL_DEPENDENCIES = host-pkgconf \