Flatpak Submodules are failing to build (certificate failures)

[XargonWan]

I had to manually build some libraries instead of relying on the shared-modules because the needed files cannot be retrieved by flatpak-builder.

Failed to download sources: module gudev: server certificate verification failed. CAfile: none CRLfile: none

https://github.com/XargonWan/RetroDECK/runs/6842156938?check_suite_focus=true#step:7:1749

I found a workaround by replacing some of them temporarly with a mirror.

More info there: https://gitlab.com/gnutls/gnutls/-/issues/1335

I am adding the various workarounds after those lines:
https://github.com/XargonWan/RetroDECK/blob/cooker/net.retrodeck.retrodeck.yml#L107-L109

[XargonWan]

Reported on Flathub: flathub/flathub#3259

[Lazorne]

Closed on flathub