Update Installation Guide

[rcomer]

🚀 Pull Request

Description

The installation guide is now out of date in a couple of places:

• Since v3.1 we do not provide platform-specific Conda downloads, so I do not think it is necessary to still list those platforms in the guide.
• Thanks to some outstanding work by @greglucas, Cartopy now has wheels 🥳, so users do not need to install any dependencies separately. I tested the pip command in a new venv on my Ubuntu laptop and it Just Worked™.

I've also changed the language we use to distinguish things.

• "Users" vs "Developers" - I think we discussed previously somewhere that this distinction is a little ambiguous because users of Iris are going to be developing something. In any case I might have reason to install a development version to do science and I might have reason to install a released version while contributing to Iris, so I prefer to distinguish by the Iris version type.
• I'm also not sure that "from source" is a helpful distinction for a pure python project. So I went for "from a git checkout" instead.

I took the liberty of adding this to the v3.7.0 project as I think it would be nice to have this in the upcoming release's docs. Obviously boot it out again if you disagree.

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Consult Iris pull request check list

[codecov]

Codecov Report

Patch and project coverage have no change.

Comparison is base (becc890) 89.37% compared to head (1b746a7) 89.37%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #5416   +/-   ##
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  Coverage   89.37%   89.37%           
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  Files          89       89           
  Lines       22443    22443           
  Branches     5381     5381           
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  Hits        20058    20058           
  Misses       1639     1639           
  Partials      746      746           

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[rcomer]

Renders like this

[pp-mo]

Yes absolutely, I think this is a worthy improvement !!
Thanks @rcomer

[pp-mo]

I'm eager to fix this, but it needs a rebase/merge to resolve conflicts.
Could we possibly get that done today @rcomer ???
I'm hoping to cut an iris3.7.0rc0 shortly

[rcomer]

OK I rebased, but git didn't tell me I had any conflicts 😕

[pp-mo]

OK I rebased, but git didn't tell me I had any conflicts 😕

OK I might have misunderstood. Can't remember what it looked like, now !

It does appear that you need to resolve the conversation you opened - I can't do it.
(To be clear, I agree -- proposal is fine)

[pp-mo]

Thanks @rcomer, it's in !
Iris 3.7 coming soon, I can feel it ..

[rcomer]

Thanks @pp-mo!