package/fetchmail: bump version to 6.4.18

Release notes:
https://sourceforge.net/p/fetchmail/mailman/message/37249830/

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/fetchmail/fetchmail.hash

@@ -1,6 +1,6 @@
-# From https://sourceforge.net/p/fetchmail/mailman/message/37215482/
-sha256  044b9a0ac03afbae7744979defe3e2e32e39141bca68fd0c8deda2ed40884fb9  fetchmail-6.4.16.tar.xz
+# From https://sourceforge.net/p/fetchmail/mailman/message/37249830/
+sha256  302dc9bcdc6927dedf375d2baaead2347557faa70d98b1da83f2409fa6fb259f  fetchmail-6.4.18.tar.xz
 # From https://sourceforge.net/projects/fetchmail/files/branch_6.4/
-sha1  ec910eed3db4d8c44469aabaf33f529334a2fdb5  fetchmail-6.4.16.tar.xz
+sha1  1fd3e4f30bd9ba7bdcaed5edfca080dc6f66377e  fetchmail-6.4.18.tar.xz
 # Locally computed:
 sha256  8e3ec4863456a26fcd1cf84fadd4146efcb2fd8515bcec482e0f2b7060108895  COPYING

package/fetchmail/fetchmail.mk

@@ -5,7 +5,7 @@
 ################################################################################
 
 FETCHMAIL_VERSION_MAJOR = 6.4
-FETCHMAIL_VERSION = $(FETCHMAIL_VERSION_MAJOR).16
+FETCHMAIL_VERSION = $(FETCHMAIL_VERSION_MAJOR).18
 FETCHMAIL_SOURCE = fetchmail-$(FETCHMAIL_VERSION).tar.xz
 FETCHMAIL_SITE = http://downloads.sourceforge.net/project/fetchmail/branch_$(FETCHMAIL_VERSION_MAJOR)
 FETCHMAIL_LICENSE = GPL-2.0; some exceptions are mentioned in COPYING