package/network-manager: drop CONTRIBUTING.md from license files

This is irrelevant as of 402ad9fe5407 (package/network-manager: bump
to version 1.22.10).

Details: https://lore.kernel.org/all/ZgXKrtfSjahxswtP@landeda/

Signed-off-by: James Hilliard <james.hilliard1@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/network-manager/network-manager.hash

@@ -3,4 +3,3 @@ sha256  722649e25362693b334371473802a729b0ec9ee283375096905f868808e74068  Networ
 # Locally computed
 sha256  8177f97513213526df2cf6184d8ff986c675afb514d4e68a404010521b880643  COPYING
 sha256  dc626520dcd53a22f727af3ee42c770e56c97a64fe3adb063799d8ab032fe551  COPYING.LGPL
-sha256  9f7f0d40116e5a0f1566b9da71e9c95738c99364e4b5437d8115aa614490372b  CONTRIBUTING.md

package/network-manager/network-manager.mk

@@ -10,7 +10,7 @@ NETWORK_MANAGER_SOURCE = NetworkManager-$(NETWORK_MANAGER_VERSION).tar.xz
 NETWORK_MANAGER_SITE = https://download.gnome.org/sources/NetworkManager/$(NETWORK_MANAGER_VERSION_MAJOR)
 NETWORK_MANAGER_INSTALL_STAGING = YES
 NETWORK_MANAGER_LICENSE = GPL-2.0+ (app), LGPL-2.1+ (libnm)
-NETWORK_MANAGER_LICENSE_FILES = COPYING COPYING.LGPL CONTRIBUTING.md
+NETWORK_MANAGER_LICENSE_FILES = COPYING COPYING.LGPL
 NETWORK_MANAGER_CPE_ID_VENDOR = gnome
 NETWORK_MANAGER_CPE_ID_PRODUCT = networkmanager
 NETWORK_MANAGER_SELINUX_MODULES = networkmanager