weave-net docker hub instructions are outdated

[morancj]

What you expected to happen?

https://github.com/weaveworks/weave/blob/34de0b10a69c2fa11f2314bfe0e449f739a96cd8/docs/release-process.md#L110-L129

The instructions on Docker Hub state:

docker plugin install --grant-all-permissions store/weaveworks/net-plugin:2.5.2

which is an older release.

The latest_release tag currently points to 2.8.1, which looks about right.

What happened?

Old version of plugin installed

How to reproduce it?

Follow the instructions on Docker Hub

Anything else we need to know?

Not that I'm aware of.