🐛 Exclude docker-data from Docker build context

The docker-data directory lives inside GITHUB_WORKSPACE, so
docker build tries to send Docker's own storage as build
context causing the build to fail.

Author: AndreMiras

.dockerignore

@@ -6,3 +6,4 @@ bin/
 *.pyc
 **/__pycache__
 *.egg-info/
+docker-data/