[electrum] update dockerfiles to unbreak the release build

Summary:
Some previous versions of packages are no longer in the Ubuntu repositories, making the release scripts fail.
I don't plan to do a release soon, but I'd like to be able to test release scripts in the test plan of other diffs.

Test Plan:
Run the build scripts and check that the "Creating Docker" stage succeeds

contrib/build-linux/appimage/build.sh
contrib/build-wine/build.sh

Reviewers: #bitcoin_abc, roqqit

Reviewed By: roqqit

Differential Revision: https://reviews.bitcoinabc.org/D16667