[CI] The conda environment files arrow/ci/conda_env_*.yml should have .txt extension

[asfimport]

The files arrow/ci/conda_env_\*.yml files are not yaml files, we should rename them to use txt extension.

Reporter: Krisztian Szucs / @kszucs
Assignee: Krisztian Szucs / @kszucs

PRs and other links:

• GitHub Pull Request #10572
• GitHub Pull Request #10656

_{Note: This issue was originally created as ARROW-6513. Please see the migration documentation for further details.}

[asfimport]

Antoine Pitrou / @pitrou:
@kszucs do you want to tackle this?

[asfimport]

Wes McKinney / @wesm:
Should we try to fix this? Shouldn't be too difficult

[asfimport]

Krisztian Szucs / @kszucs:
Issue resolved by pull request 10572
#10572