[XS] Change in coreboot[main]: util/lint: Clear syntax warnings in Python 3.12

[Felix Singer (Code Review)]

Felix Singer has submitted this change. ( https://review.coreboot.org/c/coreboot/+/85771?usp=email )

Change subject: util/lint: Clear syntax warnings in Python 3.12
......................................................................

util/lint: Clear syntax warnings in Python 3.12

Since Python 3.12, invalid escape sequences produce a SyntaxWarning;
in the future, they will produce SyntaxError.

Using raw strings clear out the warning.

Below the command used for checking the fix worked.

```
$ python3 util/lint/checkpatch_json.py
```

Link: https://docs.python.org/3.12/whatsnew/3.12.html#other-language-changes
Change-Id: I0177dc7f0d3013759879320afdb6ab548d356bc7
Signed-off-by: Ariel Otilibili 
Reviewed-on: https://review.coreboot.org/c/coreboot/+/85771
Reviewed-by: Maximilian Brune 
Tested-by: build bot (Jenkins) 
Reviewed-by: Felix Singer 
---
M util/lint/checkpatch_json.py
1 file changed, 1 insertion(+), 1 deletion(-)

Approvals:
  Felix Singer: Looks good to me, approved
  Maximilian Brune: Looks good to me, approved
  build bot (Jenkins): Verified

diff --git a/util/lint/checkpatch_json.py b/util/lint/checkpatch_json.py
index 967e898..2960b85 100755
--- a/util/lint/checkpatch_json.py
+++ b/util/lint/checkpatch_json.py
@@ -39,7 +39,7 @@
             file_path = temp[1].split(":")[0]
             line_number = temp[1].split(":")[1]
             update_struct( file_path.strip(), msg_output, str(line_number)  )
-        elif re.search("^\d+:\Z",line) != "None" and line.startswith("#"):
+        elif re.search(r"^\d+:\Z",line) != "None" and line.startswith("#"):
             file_path="/COMMIT_MSG"
             line = line.replace('#', '')
             line_number = int(line.split(":")[0]) + 2