owipcalc: change maintainer

As suggested by others, I would like to take care of this tool. I am
developing certain tools that rely on the library and also owipcalc.

Signed-off-by: Nick Hainke <vincent@systemli.org>

net/owipcalc/Makefile

@@ -7,7 +7,9 @@
 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=owipcalc
-PKG_RELEASE:=6
+PKG_RELEASE:=7
+
+PKG_MAINTAINER:=Nick Hainke <vincent@systemli.org>
 PKG_LICENSE:=Apache-2.0
 
 include $(INCLUDE_DIR)/package.mk
@@ -16,7 +18,6 @@ define Package/owipcalc
   SECTION:=utils
   CATEGORY:=Utilities
   TITLE:=Simple IPv4/IPv6 address calculator
-  MAINTAINER:=Jo-Philipp Wich <jo@mein.io>
   DEPENDS:=+libowipcalc
 endef