add more arm tags for watchtower repo

[AlexandrTyshchenko]

Please add more arm tags for watchtower repository . You can compare tags with original repository.

The main reason of this change is unify string for all arm based platforms:

docker run -d --restart=always --name watchtower -v /var/run/docker.sock:/var/run/docker.sock storjlabs/watchtower

and no need specify addition tags like it:

docker run -d --restart=always --name watchtower -v /var/run/docker.sock:/var/run/docker.sock storjlabs/watchtower:latest-arm32v6

for example: string docker run -d --restart=always --name watchtower -v /var/run/docker.sock:/var/run/docker.sock containrrr/watchtower working fine on rpi, nano-pi etc.

[aligeti]

For now we support only raspberry pi.

[Velociraptor85]

This seems to be related #2538

[ifraixedes]

Closing this issue, our watchtower image has several architecture tags publish through a docker manifest.

[AlexandrTyshchenko]

Confirmed, it fixed.