With Python 3.12 invalid escape sequences now generate warning messages.
This change fixes the problem exposed by the warning message.
```
BaseTools/Scripts\BinToPcd.py:40: SyntaxWarning: invalid escape sequence
BaseTools\Scripts\BinToPcd.py:46: SyntaxWarning: invalid escape sequence
```
Signed-off-by: Aaron Pop <aaronpop@microsoft.com>