Bump stable DUB/DMD

Author: wilzbach

posix.mak

@@ -180,7 +180,7 @@ DRUNTIME_LATEST_DIR=$G/druntime-${LATEST}
 PHOBOS_LATEST_DIR=$G/phobos-${LATEST}
 
 # stable dub and dmd versions used to build dpl-docs
-STABLE_DMD_VER=2.078.2
+STABLE_DMD_VER=2.081.1
 STABLE_DMD_ROOT=$(GENERATED)/stable_dmd-$(STABLE_DMD_VER)
 STABLE_DMD_URL=http://downloads.dlang.org/releases/2.x/$(STABLE_DMD_VER)/dmd.$(STABLE_DMD_VER).$(OS).zip
 STABLE_DMD_BIN_ROOT=$(STABLE_DMD_ROOT)/dmd2/$(OS)/$(if $(filter $(OS),osx),bin,bin$(MODEL))