Update conda_dev_env.yml

[WenjieDu]

What does this PR do?

1. ai4ts now available with conda-forge, so update conda_dev_env.yml;

[coveralls]

Pull Request Test Coverage Report for Build 10934212865

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 4 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-0.05%) to 83.316%

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Files with Coverage Reduction	New Missed Lines	%
pypots/imputation/csdi/model.py	1	84.85%
pypots/cli/doc.py	3	82.28%

Totals
Change from base Build 10933650463:	-0.05%
Covered Lines:	11191
Relevant Lines:	13432

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💛 - Coveralls