MM-63351: Use latest URL

[agarciamontoro]

Summary

Now that https://mattermost.atlassian.net/browse/CLD-7570 is resolved, we have https://latest.mattermost.com/mattermost-load-test-ng-linux, which will always point to the latest release of the tool. This PR removes the hardcoded versions in the URLs in favour of this new URL, and removes the Makefile rule prepare-release, which is no longer needed.

Ticket Link

https://mattermost.atlassian.net/browse/MM-63351

[agarciamontoro]

I'm cherry-picking to release-1.24 as soon as it's merged so that I can test the new, streamlined, release process with v1.24.1 🤓

[streamer45]

Yay! Once the simplification kicks in, what would be the best procedure to figure out which version of the tool is deployed? (e.g. I am debugging a failing comparison).

[agarciamontoro]

what would be the best procedure to figure out which version of the tool is deployed

Oh, that's a good question. We don't currently have a straightforward way to know the version that's deployed, as far as I know. We could add a new /version endpoint that returns the SHA of the commit used to build the binary and add a new command to query it. And log it as well when the server starts.

I'm curious: How would you figure it out now, without the changes in this PR?

[streamer45]

what would be the best procedure to figure out which version of the tool is deployed

Oh, that's a good question. We don't currently have a straightforward way to know the version that's deployed, as far as I know. We could add a new /version endpoint that returns the SHA of the commit used to build the binary and add a new command to query it. And log it as well when the server starts.

I'm curious: How would you figure it out now, without the changes in this PR?

I'd be looking at the deployer.json used :p I'd expect us to log which version gets downloaded at the very least.

[agarciamontoro]

I'd be looking at the deployer.json used :p I'd expect us to log which version gets downloaded at the very least.

Yeah, we cannot even rely on the name in the agent machines (even now), since any reference to the original URL is gone. I just created a ticket for this, it shouldn't be too hard to write something that makes our lives easier.