.dockerignore was not accounted for in previous push. Might be a prob…

…lem specific to using buildx in GH Actions: docker/buildx#850. Attempt at fixing it.

docker/.dockerignore

@@ -1,11 +1,10 @@
-.github
-.pytest_cache
-data
-simSPI.egg-info
-.deepsource.toml
-.gitignore
-.pre-commit-config.yaml
-dev-requirements.txt
-environment-mac.yml
-path-config.yaml
-sim-config.yaml
+**/*
+!environment.yaml
+!setup.py
+!pytest.ini
+!.codecov.yml
+!.coveragerc
+!.flake8
+!simSPI/**
+!notebooks/**
+!tests/**