package/vnstat: bump version to 2.13

Release notes:
https://github.com/vergoh/vnstat/releases/tag/v2.13
https://github.com/vergoh/vnstat/releases/tag/v2.12

Signed-off-by: Kadambini Nema <kadambini.nema@gmail.com>
Signed-off-by: Julien Olivain <ju.o@free.fr>

package/vnstat/vnstat.hash

@@ -1,3 +1,3 @@
 # Locally calculated
-sha256  babc3f1583cc40e4e8ffb2f53296d93d308cb5a5043e85054f6eaf7b4ae57856  vnstat-2.11.tar.gz
+sha256  c9fe19312d1ec3ddfbc4672aa951cf9e61ca98dc14cad3d3565f7d9803a6b187  vnstat-2.13.tar.gz
 sha256  8177f97513213526df2cf6184d8ff986c675afb514d4e68a404010521b880643  COPYING

package/vnstat/vnstat.mk

@@ -4,7 +4,7 @@
 #
 ################################################################################
 
-VNSTAT_VERSION = 2.11
+VNSTAT_VERSION = 2.13
 VNSTAT_SITE = http://humdi.net/vnstat
 VNSTAT_LICENSE = GPL-2.0
 VNSTAT_LICENSE_FILES = COPYING