feat(debian): add bullseye support

postgres/codenamemap.yaml

@@ -60,12 +60,14 @@
 {{ debian_codename('jessie', '9.4') }}
 {{ debian_codename('stretch', '9.6') }}
 {{ debian_codename('buster', '11') }}
+{{ debian_codename('bullseye', '13') }}
 
 # `oscodename` grain has long distro name
 # if `lsb-release` package not installed
 {{ debian_codename('jessie', '9.4', 'Debian GNU/Linux 8 (jessie)') }}
 {{ debian_codename('stretch', '9.6', 'Debian GNU/Linux 9 (stretch)') }}
 {{ debian_codename('buster', '11', 'Debian GNU/Linux 10 (buster)') }}
+{{ debian_codename('bullseye', '13', 'Debian GNU/Linux 11 (bullseye)') }}
 
 ## Ubuntu
 # http://apt.postgresql.org/pub/repos/apt/dists/