fix(elixir): add common target dependencies for `%-elixir-pkg`

For installing Hex/Rebar and downloading dependencies on a fresh
clone.

Makefile

@@ -226,7 +226,7 @@ $(REL_PROFILES:%=%-elixir) $(PKG_PROFILES:%=%-elixir): $(COMMON_DEPS) $(ELIXIR_C
 .PHONY: $(REL_PROFILES:%=%-elixir-pkg)
 define gen-elixir-pkg-target
 # the Elixir places the tar in a different path than Rebar3
-$1-elixir-pkg:
+$1-elixir-pkg: $(COMMON_DEPS) $(ELIXIR_COMMON_DEPS) mix-deps-get
 	@env TAR_PKG_DIR=_build/$1-pkg \
 	     IS_ELIXIR=yes \
 	     $(BUILD) $1-pkg pkg