Fix Python package versions.
Earlier changes to the get-version script were not adopted by the Python
SDK Makefile. This caused package publishing to skip uploads due to
missing versions.
PROJECT_NAME := Pulumi Python SDK
LANGHOST_PKG := github.com/pulumi/pulumi/sdk/python/cmd/pulumi-language-python
-VERSION := $(shell ../../scripts/get-py-version)
+VERSION := $(shell ../../scripts/get-py-version HEAD)
PYENV := ./env
PYENVSRC := $(PYENV)/src
