Add env vars for devcontainer-release

Author: stuartleeks

Makefile

@@ -9,6 +9,11 @@ ifdef DEVCONTAINER
 	$(error This target can only be run outside of the devcontainer as it mounts files and this fails within a devcontainer. Don't worry all it needs is docker)
 endif
 	@docker run -v ${PWD}:${PWD} \
+		-e BUILD_NUMBER="${BUILD_NUMBER}" \
+		-e IS_CI="${IS_CI}" \
+		-e IS_PR="${IS_PR}" \
+		-e BRANCH="${BRANCH}" \
+		-e GITHUB_TOKEN="${GITHUB_TOKEN}" \
 		--entrypoint /bin/bash \
 		--workdir "${PWD}" \
 		devcontainer-cli \