E. F-Droid needs `submodules: true`

[sunkup]

After D the translations live in a git submodule, and F-Droid doesn't fetch submodules unless the build recipe says so. I checked, and ours currently doesn't.

https://gitlab.com/fdroid/fdroiddata/-/blob/master/metadata/at.bitfire.davdroid.yml?ref_type=heads

submodules: true was set on every build up to 4.3.4.1-ose and then dropped from 4.3.5-ose onwards - prob when the old cert4android/ical4android/vcard4android submodules were replaced by Gradle dependencies. The current entry (4.5.19) only has subdir, gradle and prebuild.

What the flag does, per the build metadata reference: "causes git submodule update --init --recursive to be executed after the source is cloned".

• Make sure davx5-translations is public - F-Droid clones anonymously
• Merge request against fdroiddata adding submodules: true to the latest build entry in metadata/at.bitfire.davdroid.yml.

[sunkup]

Wait until release is ready (or close to)

https://gitlab.com/fdroid/fdroiddata/-/merge_requests/46294

[ArnyminerZ]

update this MR with a new build block WHEN the release is ready (or close to)

So I guess this is done (merging the PR should be made by the F-Droid team), so marking it "In Progress"