package/python-docker: add CPE variables

cpe:2.3:a:docker:docker-py is a valid CPE identifier for this package:

  https://nvd.nist.gov/products/cpe/search/results?namingFormat=2.3&keyword=cpe%3A2.3%3Aa%3Adocker%3Adocker-py

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/python-docker/python-docker.mk

@@ -10,5 +10,7 @@ PYTHON_DOCKER_SITE = https://files.pythonhosted.org/packages/de/54/a822d7116ff2f
 PYTHON_DOCKER_SETUP_TYPE = setuptools
 PYTHON_DOCKER_LICENSE = Apache-2.0
 PYTHON_DOCKER_LICENSE_FILES = LICENSE
+PYTHON_DOCKER_CPE_ID_VENDOR = docker
+PYTHON_DOCKER_CPE_ID_PRODUCT = docker-py
 
 $(eval $(python-package))