repo: stop tracking Python bytecode caches

The compiled `__pycache__/*.pyc` files were committed by accident. They
are interpreter-version specific build artifacts, regenerated on every
run, so they only add binary churn to diffs and can shadow edited
sources with a stale cache.

Untrack them and add a .gitignore so they stay out.

Signed-off-by: Yves Brissaud <yves@dagger.io>

Author: eunomie

.gitignore

@@ -0,0 +1,3 @@
+# Python bytecode caches
+__pycache__/
+*.py[cod]