Migrate micromamba setup action

[minhkhul]

This PR might fix this problem thst's blocking blog build:

Warning: This action is deprecated and no longer maintained. Please use mamba-org/setup-micromamba instead. See [https://github.com/mamba-org/provision-with-micromamba#migration-to-setup-micromamba](https://github.com/mamba-org/provision-with-micromamba#migration-to-setup-micromamba%60) for a migration guide.

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[minhkhul]

Build time Set up step is 50 minutes with this new setup action (vs max 5 mins before). Will check for alternative way to go about this before settling.

[melange396]

looks like it worked but it took a loooong time -- almost 2h!!! https://github.com/cmu-delphi/www-main/actions/runs/11039802772/job/30666229264

i ran it again to see if its a fluke or if it will pick up cache from the prior run: https://github.com/cmu-delphi/www-main/actions/runs/11041452519/job/30671730241

[melange396]

@minhkhul looks like our messages crossed in the night! This action was running fairly regularly at around 13 minutes with occasional excursions... Either way, its a large departure from before, but we should wait and see what happens with the second run.

[melange396]

The second run did not have appreciable time savings. 1.5-2h is an incredibly long time to wait for this, we should see what else we can do to speed it up. The "Create environment" step has a lot of output that looks similar to the "Run mamba-org/setup-micromamba@v1" step, perhaps there is some repetition that can be removed? That is probably not enough though -- even half the runtime is still much longer than the job used to take.

[minhkhul]

ye I've been looking into other options for building the blog today. I'll close this one for now.

[minhkhul]

Added caching, which is working, bringing it down to 4 min. https://github.com/cmu-delphi/www-main/actions/runs/11096551953/job/30830681257

[melange396]

lgtm!