Copy channels before reversing

[bollwyvl]

• fixes Channel priority changed in 2.1.0 release #160
• use .slice to copy channels before reversing
• updates package-lock.json after installing from fresh environment
• add "typical" channel line-up to example environment
• add test of environment-patched.yml? Hoist to output?

[bollwyvl]

By inspection, this is fixing the issue:
https://github.com/conda-incubator/setup-miniconda/pull/161/checks?check_run_id=2222447371#step:3:257

the order is as set in the original yaml. I don't know how to simply retrieve the logs from within the action (if that's even possible), but otherwise this is ready for review.

[bollwyvl]

I guess we could hoist the "effective used environment" to an action output...

[jaimergp]

So what was the issue? .reverse() acting in place instead of returning a reversed "view" and that can leave the list of channel in the wrong state for the next operation?

[bollwyvl]

acting in place instead of returning a reversed "view"

right, gory details on #160

[jaimergp]

Huh, that's surprising indeed, at least coming from the Python world. If that's the case and this fixes the misbehavior, this LGTM.

How would you like to check for the right behavior? Diffing conda lists?

[bollwyvl]

Yeah dunno, re: testing.... Maybe something in conda-meta/history?

[goanpeca]

Looks good @bollwyvl

Should I make a 2.1.1 release?

[bollwyvl]

Good by me to release unless we can figure out what the other fresh issue is regarding python-version... #158... Might be a change, but not necessarily a _bug_ whereas this definitely was.