Update build.yml

[ghost]

github not use Flavors.

[UjuiUjuMandan]

@2dust Sorry, please revert this. It's necessary for Reproducible Builds.

The workflow is like this:

1. GitHub Actions builds and uploads the APKs of both flavors to releases, one is with -fdroid suffix, the other is not.
2. fdroidserver builds the APKs of fdroid flavors.
3. fdroidserver fetches your APKs with -fdroid suffix from GitHub Releases.
4. fdroidserver compares them. If passed, releases it with copying your signatures.

[UjuiUjuMandan]

The sed patching is really unnecessary; I have only seen downstream patches of upstream; how opposite?

[UjuiUjuMandan]

I'll revert that after the veery slow diffoscope completed.

[ghost]

😂a little trouble, all right.