Deprecation warning due to invalid escape sequences in Python 3.7

```
find . -iname '*.py' | grep -v example | xargs -P 4 -I{} python3.8 -Wall -m py_compile {}
./scripts/new_version.py:47: DeprecationWarning: invalid escape sequence \d
  mod = re.sub("__version__ = '[\d\.]+'",
./scripts/commit_version.py:25: DeprecationWarning: invalid escape sequence \d
  mod = re.sub("__version__ = '[\d\.]*\.dev0'",
```