pmb: Use raw strings for regexes (MR 2525)

See https://docs.astral.sh/ruff/rules/unraw-re-pattern

pmb/aportgen/core.py

@@ -15,7 +15,7 @@ def indent_size(line: str) -> int:
     """
     Number of spaces at the beginning of a string.
     """
-    matches = re.findall("^[ ]*", line)
+    matches = re.findall(r"^[ ]*", line)
     if len(matches) == 1:
         return len(matches[0])
     return 0

pmb/qemu/run.py

@@ -301,7 +301,7 @@ def resize_image(img_size_new: str, img_path: Path) -> None:
     img_size = os.path.getsize(img_path)
 
     # Make sure we have at least 1 integer followed by either M or G
-    pattern = re.compile("^[0-9]+[M|G]$")
+    pattern = re.compile(r"^[0-9]+[M|G]$")
     if not pattern.match(img_size_new):
         raise RuntimeError("IMAGE_SIZE must be in [M]iB or [G]iB, e.g. 2048M or 2G")