examples/gcoap: Add 'obs' attribute to resource
examples/gcoap: Add 'obs' attribute to resource

OTAkeys/RIOT,basilfx/RIOT,OTAkeys/RIOT,aeneby/RIOT,aeneby/RIOT,kYc0o/RIOT,miri64/RIOT,kYc0o/RIOT,authmillenon/RIOT,smlng/RIOT,aeneby/RIOT,OlegHahm/RIOT,smlng/RIOT,ant9000/RIOT,josephnoir/RIOT,toonst/RIOT,OlegHahm/RIOT,x3ro/RIOT,kYc0o/RIOT,mtausig/RIOT,yogo1212/RIOT,smlng/RIOT,basilfx/RIOT,aeneby/RIOT,authmillenon/RIOT,toonst/RIOT,x3ro/RIOT,x3ro/RIOT,kaspar030/RIOT,toonst/RIOT,OlegHahm/RIOT,RIOT-OS/RIOT,jasonatran/RIOT,toonst/RIOT,RIOT-OS/RIOT,basilfx/RIOT,ant9000/RIOT,authmillenon/RIOT,kaspar030/RIOT,ant9000/RIOT,mtausig/RIOT,miri64/RIOT,yogo1212/RIOT,ant9000/RIOT,kaspar030/RIOT,authmillenon/RIOT,RIOT-OS/RIOT,miri64/RIOT,jasonatran/RIOT,mtausig/RIOT,OTAkeys/RIOT,jasonatran/RIOT,x3ro/RIOT,OlegHahm/RIOT,authmillenon/RIOT,OTAkeys/RIOT,basilfx/RIOT,basilfx/RIOT,josephnoir/RIOT,smlng/RIOT,aeneby/RIOT,yogo1212/RIOT,OTAkeys/RIOT,kaspar030/RIOT,josephnoir/RIOT,yogo1212/RIOT,josephnoir/RIOT,x3ro/RIOT,kYc0o/RIOT,RIOT-OS/RIOT,josephnoir/RIOT,toonst/RIOT,mtausig/RIOT,jasonatran/RIOT,kYc0o/RIOT,mtausig/RIOT,OlegHahm/RIOT,kaspar030/RIOT,miri64/RIOT,RIOT-OS/RIOT,miri64/RIOT,yogo1212/RIOT,smlng/RIOT,yogo1212/RIOT,authmillenon/RIOT,ant9000/RIOT,jasonatran/RIOT