Permit the '@' character in files/

This will allow for systemd template units to be stored in files/
without mangling the filename.

PMS says nothing about filenames in files/ so we can really permit
whatever we find palatable.

Signed-off-by: Mike Gilbert <[email protected]>

src/pkgcheck/checks/pkgdir.py

@@ -19,6 +19,10 @@
 allowed_filename_chars.update(chr(x) for x in range(ord("0"), ord("9") + 1))
 allowed_filename_chars.update([".", "-", "_", "+", ":"])
 
+# Allow '@' in files/
+allowed_filesdir_chars = allowed_filename_chars.copy()
+allowed_filesdir_chars.add("@")
+
 
 class MismatchedPN(results.PackageResult, results.Error):
     """Ebuilds that have different names than their parent directory."""
@@ -289,7 +293,7 @@ def feed(self, pkgset):
                             yield SizeViolation(
                                 pjoin(base_dir, filename), file_stat.st_size, pkg=pkg
                             )
-                    if banned_chars := set(filename) - allowed_filename_chars:
+                    if banned_chars := set(filename) - allowed_filesdir_chars:
                         yield BannedCharacter(
                             pjoin(base_dir, filename), sorted(banned_chars), pkg=pkg
                         )