Remove x86_64-only restriction

[mwilck]

With recent changes in the dependency generator, we are now able to download the aarch64 dependencies as well.

[flathubbot]

Started test build 85148

[flathubbot]

Build 85148 failed

[mwilck]

bot, build

[flathubbot]

Queued test build for org.audiveris.audiveris.

[flathubbot]

Started test build 85149

[flathubbot]

Build 85149 failed

[flathubbot]

Started test build 85150

[mwilck]

bot, build

[flathubbot]

Queued test build for org.audiveris.audiveris.

[flathubbot]

Started test build 85151

[flathubbot]

Build 85150 successful
To test this build, install it from the testing repository:

flatpak install --user https://dl.flathub.org/build-repo/67798/org.audiveris.audiveris.flatpakref

[flathubbot]

Build 85151 successful
To test this build, install it from the testing repository:

flatpak install --user https://dl.flathub.org/build-repo/67799/org.audiveris.audiveris.flatpakref