ubuntu-cpc: Allow comments in series files

An upcoming addition of the disk-image target to several series files will
required some explanation.  Without comment support in series files that
is not possible.  This patch adds support for comments in series files.

live-build/ubuntu-cpc/hooks.d/make-hooks

@@ -161,7 +161,7 @@ class MakeHooks:
             with open(series_file, "r", encoding="utf-8") as fp:
                 for line in fp:
                     line = line.strip()
-                    if not line:
+                    if not line or line.startswith("#"):
                         continue
                     m = re.match(r"^\s*depends\s+(\S+.*)$", line)
                     if m: