MT#55890 lib/set_debian_info: add support for Debian/bookworm

Until Debian/bookworm is getting the new stable release, it's
known as bookworm/sid in /etc/debian_version.

Fixes:

| sp1: Error: Cannot process template '/etc/ngcp-config/templates/etc/default/ngcp-proxy.tt2':
|   undef error - Error: unsupported Debian codename bookworm at (eval 16) line 30.

Change-Id: Idfe0119ce47cbe8fdcbcd57e9a2c2014e93cf6e1

lib/set_debian_info

@@ -25,6 +25,8 @@
     9 => 'stretch',
     10 => 'buster',
     11 => 'bullseye',
+    12 => 'bookworm',
+    'bookworm/sid' => 'bookworm',
   );
   my %codenames = map { $versions{$_} => $_ } keys %versions;