Update release instructions for release branch

[rfratto]

A release branch has been added to always refer to the latest release tag. This must be updated as part of the post-release process. Instructions on doing this have been added to the maintainers manual.

[cstyan]

LGTM, but personally that step doesn't seem to be that valuable if the only benefit is that the install instructions could be generic.

[rfratto]

Fair argument, we only need it so we don't have to keep updating grafana.com with new instructions every time we do a release here.

[cstyan]

Can it not just say pick the latest version from https://github.com/grafana/agent/releases and substitute it into your curl/wget/etc command?

[rfratto]

Sorry, I'm being too vague here.

The installation script as it is now asks you for your remote write URL and basic auth info. The instructions on grafana.com will modify the command slightly to pass that through environment variables so the user isn't prompted for input. So in that case it'll just be a "copy this, paste it, run it, and the Agent is installed and sending data to Grafana Cloud."

[cstyan]

In that case, if the release script downloads via https://github.com/grafana/agent/releases/latest via a call that allows redirect (curl -L for example) you'll always get the latest release.

[rfratto]

I agree with the point here: we should definitely have a script that installs the latest release rather than having to manage a release branch.

Unfortunately, I do want to move this forward so I'm going to merge this for now and open an issue to improve this process.