Mechanical change to fix SyntaxWarnings on regexes

[ckuethe]

Description

Fixes #1680

Mechanical change to make the regex strings in utils.py be raw strings ("\d+" -> r"\d+"), thus making SyntaxWarnings go away. Easier to read than escaping the backslashes, eg. "\d+" -> "\\d+"

Found while running a scan on my AWS project; scan completes successfully and produces valid results after this change but with no more SyntaxWarning

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works (optional)
• New and existing unit tests pass locally with my changes