boot-qemu.py: Use re.MULTILINE instead of re.M

As suggested by the refurb rules from ruff:

  FURB167 [*] Use of regular expression alias `re.M`
     --> boot-qemu.py:140:93
      |
  138 |         strings_stdout = strings.stdout.decode(encoding='utf-8', errors='ignore')
  139 |
  140 |         if not (match := re.search(r'^Linux version (\d+\.\d+\.\d+)', strings_stdout, flags=re.M)):
      |                                                                                             ^^^^
  141 |             raise RuntimeError(f"Could not find Linux version in {self.kernel}?")
      |
  help: Replace with `re.MULTILINE`

Signed-off-by: Nathan Chancellor <nathan@kernel.org>

Author: nathanchance

boot-qemu.py

@@ -136,7 +136,11 @@ def _get_kernel_ver_tuple(self, decomp_prog: str) -> tuple[int, ...]:
         strings = subprocess.run('strings', capture_output=True, check=True, input=decomp.stdout)
         strings_stdout = strings.stdout.decode(encoding='utf-8', errors='ignore')
 
-        if not (match := re.search(r'^Linux version (\d+\.\d+\.\d+)', strings_stdout, flags=re.M)):
+        if not (
+            match := re.search(
+                r'^Linux version (\d+\.\d+\.\d+)', strings_stdout, flags=re.MULTILINE
+            )
+        ):
             raise RuntimeError(f"Could not find Linux version in {self.kernel}?")
 
         return tuple(int(x) for x in match.groups()[0].split('.'))