CURATOR-204 Update parent pom to apache:16
CURATOR-204 Update parent pom to apache:16

Update parent pom to apache 16 and remove duplicative version declarations. Let apache handle it where we don't conflict.

mosoft521/curator,dragonsinth/curator,ouyangkongtong/curator-1,madrob/curator,serranom/curator,fengbaicanhe/curator,apache/curator,oza/curator,jinwen/curator,madrob/curator,yepuv1/curator.net,apache/curator,xuzha/curator,yepuv1/curator.net,digital-abyss/curator,digital-abyss/curator,ouyangkongtong/curator-1,serranom/curator,jithu21/curator,mosoft521/curator,wfxiang08/curator,joelittlejohn/curator,dragonsinth/curator,wfxiang08/curator,xuzha/curator,joelittlejohn/curator,yepuv1/curator.net,jithu21/curator,jinwen/curator,fengbaicanhe/curator,oza/curator