Update is broken in Ubuntu 20.04

[stdedos]

Describe the bug
A clear and concise description of what the bug is.

To Reproduce

Updating is broken? 😕

$ sudo apt-get upgrade xpra
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Calculating upgrade... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 xpra : Depends: libc but it is not installable
        Depends: libx11 but it is not installable
        Depends: libxcomposite but it is not installable
        Depends: libxdamage but it is not installable
        Depends: libxtst but it is not installable
        Depends: libxkbfile but it is not installable
        Depends: libxres but it is not installable
        Depends: libdrm but it is not installable
        Depends: liblz4 but it is not installable
        Recommends: xpra-codecs but it is not going to be installed
        Recommends: libsystemd but it is not installable
        Recommends: libprocps but it is not installable
E: Broken packages
$ apt-cache madison xpra
      xpra | 5.0-r32135-1 | https://xpra.org/beta focal/main amd64 Packages
      xpra | 5.0-r32124-1 | https://xpra.org/beta focal/main amd64 Packages
      xpra | 5.0-r32108-1 | https://xpra.org/beta focal/main amd64 Packages
      xpra | 5.0-r32100-1 | https://xpra.org/beta focal/main amd64 Packages
      xpra | 5.0-r32078-1 | https://xpra.org/beta focal/main amd64 Packages
      xpra |   4.4-r0-1 | https://xpra.org focal/main amd64 Packages
      xpra |   4.4-r0-1 | https://xpra.org/beta focal/main amd64 Packages
      xpra | 4.3.4-r0-1 | https://xpra.org focal/main amd64 Packages
      xpra | 4.3.3-r0-1 | https://xpra.org focal/main amd64 Packages
      xpra | 4.3.2-r0-1 | https://xpra.org focal/main amd64 Packages
      xpra | 4.3.1-r0-1 | https://xpra.org focal/main amd64 Packages
      xpra |   4.3-r0-1 | https://xpra.org focal/main amd64 Packages
      xpra | 4.2.3-r12-2 | https://xpra.org focal/main amd64 Packages
      xpra | 4.2.3-r0-1 | https://xpra.org focal/main amd64 Packages
      xpra | 4.2.2-r0-1 | https://xpra.org focal/main amd64 Packages
      xpra | 4.2.1-r0-1 | https://xpra.org focal/main amd64 Packages
      xpra |   4.2-r0-1 | https://xpra.org focal/main amd64 Packages
      xpra | 4.1.3-r1-1 | https://xpra.org focal/main amd64 Packages
      xpra | 4.1.2-r2-1 | https://xpra.org focal/main amd64 Packages
      xpra | 4.1.1-r28-1 | https://xpra.org focal/main amd64 Packages
      xpra | 4.1.1-r5-1 | https://xpra.org focal/main amd64 Packages
      xpra | 4.1-r28561-1 | https://xpra.org focal/main amd64 Packages
      xpra | 4.0.6-r28351-1 | https://xpra.org focal/main amd64 Packages
      xpra | 4.0.5-r27999-1 | https://xpra.org focal/main amd64 Packages
      xpra | 4.0.4-r27557-1 | https://xpra.org focal/main amd64 Packages
      xpra | 4.0.3-r27082-1 | https://xpra.org focal/main amd64 Packages
      xpra | 4.0.2-r26625-1 | https://xpra.org focal/main amd64 Packages
      xpra | 4.0.1-r26379-1 | https://xpra.org focal/main amd64 Packages
      xpra | 4.0-r26306-1 | https://xpra.org focal/main amd64 Packages
      xpra | 3.0.6+dfsg1-1build1 | http://fi.archive.ubuntu.com/ubuntu focal/universe amd64 Packages

System Information (please complete the following information):

• Server OS: Ubuntu 20.04.5 LTS
• Xpra Server Version (see above)
• Xpra Client Version (see above)*

Additional context
Add any other context about the problem here.
Please see "reporting bugs" in the wiki section.

[totaam]

Caused by #3651.
Had to replace the "auto" dependencies with manual ones since it was totally not obvious how to do it "correctly" for split packages.
Clearly, I got it wrong.

[stdedos]

 *** 5.0-r32108-1 500

is safe

[totaam]

And so I had to learn how to mangle shlibdeps and dh_install... 22627f8 + bd1e526 should have fixed this.

The beta repository has updated packages for Ubuntu 20.04.

[stdedos]

Verified that update

Unpacking xpra (5.0-r32146-1) over (5.0-r32078-1) ...

works

» xpra --version
xpra v5.0-r32146 (gbd1e526c1) beta