Fails to run - unable to locate package dirmngr

[Le5tes]

Description

I installed the program with pip3 but it gave the following errors:

INFO:Docker Client:Reading package lists...
INFO:Docker Client:Building dependency tree...
INFO:Docker Client:
Reading state information...
INFO:Docker Client:Package gnupg2 is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
However the following packages replace it:
  gpgv
INFO:Docker Client:E: Unable to locate package dirmngr
E: Package 'gnupg2' has no installation candidate

ERROR:Docker Client:Error building Docker image. The follow error was caught:
The command '/bin/sh -c apt-get update && apt-get install --no-install-recommends -y       dirmngr       gnupg2     && rm -rf /var/lib/apt/lists/*' returned a non-zero code: 100
NoneType: None

I think dirmngr and gnupg2 are outdated and no longer available

Full trace

$ ros_cross_compile . --rosdistro galactic --arch aarch64 --os ubuntu 
INFO:Rosdep Gatherer:Building rosdep collector image: ros_cross_compile:rosdep
INFO:Docker Client:Step 1/10 : FROM ubuntu:bionic
INFO:Docker Client: ---> ad080923604a
INFO:Docker Client:Step 2/10 : RUN apt-get update && apt-get install --no-install-recommends -y       dirmngr       gnupg2     && rm -rf /var/lib/apt/lists/*
INFO:Docker Client: ---> Running in 38a37b207b86
INFO:Docker Client:Err:1 http://security.ubuntu.com/ubuntu bionic-security InRelease
  Temporary failure resolving 'security.ubuntu.com'
INFO:Docker Client:Err:2 http://archive.ubuntu.com/ubuntu bionic InRelease
  Temporary failure resolving 'archive.ubuntu.com'
INFO:Docker Client:Err:3 http://archive.ubuntu.com/ubuntu bionic-updates InRelease
  Temporary failure resolving 'archive.ubuntu.com'
INFO:Docker Client:Err:4 http://archive.ubuntu.com/ubuntu bionic-backports InRelease
  Temporary failure resolving 'archive.ubuntu.com'
INFO:Docker Client:Reading package lists...
INFO:Docker Client:W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/bionic/InRelease  Temporary failure resolving 'archive.ubuntu.com'
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/bionic-updates/InRelease  Temporary failure resolving 'archive.ubuntu.com'
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/bionic-backports/InRelease  Temporary failure resolving 'archive.ubuntu.com'
W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/bionic-security/InRelease  Temporary failure resolving 'security.ubuntu.com'
W: Some index files failed to download. They have been ignored, or old ones used instead.

INFO:Docker Client:Reading package lists...
INFO:Docker Client:Building dependency tree...
INFO:Docker Client:
Reading state information...
INFO:Docker Client:Package gnupg2 is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
However the following packages replace it:
  gpgv
INFO:Docker Client:E: Unable to locate package dirmngr
E: Package 'gnupg2' has no installation candidate

ERROR:Docker Client:Error building Docker image. The follow error was caught:
The command '/bin/sh -c apt-get update && apt-get install --no-install-recommends -y       dirmngr       gnupg2     && rm -rf /var/lib/apt/lists/*' returned a non-zero code: 100
NoneType: None
Traceback (most recent call last):
  File "/home/timwilliamson/.local/bin/ros_cross_compile", line 8, in <module>
    sys.exit(main())
  File "/home/timwilliamson/.local/lib/python3.8/site-packages/ros_cross_compile/ros_cross_compile.py", line 237, in main
    cross_compile_pipeline(args, data_collector, platform)
  File "/home/timwilliamson/.local/lib/python3.8/site-packages/ros_cross_compile/ros_cross_compile.py", line 224, in cross_compile_pipeline
    stage(platform, docker_client, ros_workspace_dir, options, data_collector)
  File "/home/timwilliamson/.local/lib/python3.8/site-packages/ros_cross_compile/dependencies.py", line 131, in __call__
    gather_rosdeps(
  File "/home/timwilliamson/.local/lib/python3.8/site-packages/ros_cross_compile/dependencies.py", line 63, in gather_rosdeps
    docker_client.build_image(
  File "/home/timwilliamson/.local/lib/python3.8/site-packages/ros_cross_compile/docker_client.py", line 73, in build_image
    self._process_build_log(log_generator)
  File "/home/timwilliamson/.local/lib/python3.8/site-packages/ros_cross_compile/docker_client.py", line 83, in _process_build_log
    raise docker.errors.BuildError(error_line)
docker.errors.BuildError: The command '/bin/sh -c apt-get update && apt-get install --no-install-recommends -y       dirmngr       gnupg2     && rm -rf /var/lib/apt/lists/*' returned a non-zero code: 100

System (please complete the following information)

• OS: Ubuntu Focal
• ROS 2 Distro: Galactic