element-desktop: update electron 19 -> 20
element-desktop: update electron 19 -> 20

upstream updated the electron dependency on 2022/08/19:
- <https://github.com/vector-im/element-desktop/commit/868e45a4a23f7d56c7bfd9ccc95b65a1c55aff2a>

built for x86_64 and aarch64; tested on x86_64 under sway

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