kpeoplesink does not build for armv7 on v21.03

kpeoplesink fails to build for armv7 on v21.03, because sink-dev is missing.

https://builds.sr.ht/~postmarketos/job/440554

sink has armv7 disabled, even in Alpine edge:

arch="aarch64 ppc64le x86 x86_64" # limited by flatbuffers

https://git.alpinelinux.org/aports/tree/community/sink/APKBUILD

and flatbuffers also has armv7 disabled, even in Alpine edge:

arch="aarch64 ppc64le x86 x86_64" # arm* gets bus error

https://git.alpinelinux.org/aports/tree/community/flatbuffers/APKBUILD

However, for Alpine edge, binary packages for flatbuffers and sink for armv7 exist. Looks like they were not properly deleted from the repository, when the arch was disabled:

The v3.13 branch of Alpine does not have them.

@PureTryOut: please look into this.

Can you simply enable flatbuffers and sink for armv7, or what's with the mentioned bus error?
If it can be enabled on edge, please backport the change to Alpine v3.13. (Or if that's not possible, submit a MR to fork the packages for pmaports temp on v21.03.)

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