Update installation instructions

[glatterf42]

Closes #698 and #718. According to the notes I gathered during recent installation/CI runs, this PR

• recommends the libmamba solver when installing via conda
• corrects the dependency arguments (or adds them) when using pip
• recommends adding the main repo as remote upstream and fetches the tags from there

How to review

• Read the diff and note that the CI checks all pass.
• Build the documentation and look at the installation page.

PR checklist

• Continuous integration checks all ✅
  Except for macos-latest-py3.7 per Track/work around actions/setup-python#682 ixmp#484.
• Add or expand tests; coverage checks both ✅
• Add, expand, or update documentation.
• Update release notes. Not applicable.

[glatterf42]

@khaeru Do you think we should mention not installing jpype version 1.4.1 in the installation instructions? I was thinking of adding that to the 'known issues', but then I saw that you removed the temporary workaround in iiasa/ixmp#463, so I don't know if this is still relevant?

[codecov]

Codecov Report

Merging #720 (1b97c02) into main (6dee23a) will not change coverage.
The diff coverage is n/a.

@@          Coverage Diff          @@
##            main    #720   +/-   ##
=====================================
  Coverage   94.4%   94.4%           
=====================================
  Files         43      43           
  Lines       3448    3448           
=====================================
  Hits        3257    3257           
  Misses       191     191           

[khaeru]

@khaeru Do you think we should mention not installing jpype version 1.4.1 in the installation instructions? I was thinking of adding that to the 'known issues', but then I saw that you removed the temporary workaround in iiasa/ixmp#463, so I don't know if this is still relevant?

It appears to have resolved itself. Both the ixmp and message-ix "pytest" CI workflows appear to be using JPype1 v1.4.1, and test_del_ts is passing. We don't have a concrete understanding of what was causing the issue: we only know that it appeared around the time JPype1 v1.4.1 appeared.

tl;dr—I'd agree with your judgement that we don't need to specifically mention it in the install instructions.

[khaeru]

Thanks @glatterf42! 🚀