Rename Python 3 markdown files into 'python'

```
for f in $(find . -iname "*python3*" | grep -vE 'git'); do
  fnew=$(echo "$f" | sed 's/python3/python/')
  git mv "$f" "$fnew"
done

1 files changed, 0 insertions, 0 deletions

diff --git a/cs-cz/python3.html.markdown b/cs-cz/python.html.markdown
index bd3690a8..bd3690a8 100644
--- a/cs-cz/python3.html.markdown
+++ b/cs-cz/python.html.markdown