gnunet: revert accidentally committed version bump

0.12.0 tarballs aren't out yet, I accidentally committed the changed
version in commit b6a9bd3bf3
("gnurl: update to version 7.67.0").
Revert gnunet back to 0.11.8.

Reported-by: Sebastian Kemper <sebastian_ml@gmx.net>
Signed-off-by: Daniel Golle <daniel@makrotopia.org>

net/gnunet/Makefile

@@ -2,7 +2,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=gnunet
 
-PKG_VERSION:=0.12.0
+PKG_VERSION:=0.11.8
 PKG_RELEASE:=1
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
 PKG_SOURCE_URL:=@GNU/gnunet