mk-sbuild create error due to bullseye security move

[Nick Brown]

Probably very similar to 1916633 reported and fixed in pbuilder-dist.

while using `mk-sbuild --name foobar bullseye`

```
E: The repository 'http://security.debian.org bullseye/updates Release' does not have a Release file.
```

Bullseye changed the format of security suite: https://www.debian.org/releases/bullseye/amd64/release-notes/ch-information.en.html#security-archive

and should look like:

```
deb https://deb.debian.org/debian-security bullseye-security main contrib
```

while mk-sbuild is still generating the older format as found in buster and earlier:

```
deb http://security.debian.org/ bullseye/updates main non-free contrib
```

at this bit of the code: https://git.launchpad.net/ubuntu/+source/ubuntu-dev-tools/tree/mk-sbuild#n661

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Launchpad Janitor (janitor)]

This bug was fixed in the package ubuntu-dev-tools - 0.192

---------------
ubuntu-dev-tools (0.192) unstable; urgency=medium

  [ Benjamin Drung ]
  * sponsor-patch:
    + Ignore exit code 1 of debdiff call.
    + Use --skip-patches instead of --no-preparation with dpkg-source -x.
  * Demote bzr/brz from Recommends to Suggests, as nowadays git is the way.
    Closes: #940531
  * Use PEP440 compliant version in setup.py (LP: #1991606)
  * Fix issues found by flake8 on the Python scripts
  * Check Python scripts with flake8 again
  * Format Python code with black and run black during package build
  * Sort Python imports with isort and run isort during package build
  * Replace deprecated optparse with argparse
  * requestbackport: Remove useless loop from locate_package
  * reverse-depends: Restore field titles format
  * test: Fix deprecated return value for test case
  * Fix all errors and warnings found by pylint and implement most refactorings
    and conventions. Run pylint during package build again.
  * Bump Standards-Version to 4.6.2
  * Drop unneeded X-Python3-Version from d/control

  [ Masahiro Yamada ]
  * mk-sbuild:
    + Handle the new location of the Debian bullseye security archive.
      Closes: #1001832; LP: #1955116

  [ Mattia Rizzolo ]
  * requestbackport:
    + Apply patch from Krytarik Raido and Unit 193 to update the template and
      workflow after the new Ubuntu Backport process has been established.
      LP: #1959115

 -- Benjamin Drung <email address hidden> Wed, 01 Feb 2023 12:45:15 +0100