Update ansible-test sanity command. (#31958)

* Use correct pip version in ansible-test.
* Add git fallback for validate-modules.
* Run sanity tests in a docker container.
* Use correct python version for sanity tests.
* Pin docker completion images and add default.
* Split pylint execution into multiple contexts.
* Only test .py files in use-argspec-type-path test.
* Accept identical python interpeter name or binary.
* Switch cloud tests to default container.
* Remove unused extras from pip install.
* Filter out empty pip commands.
* Don't force running of pip list.
* Support delegation for windows and network tests.
* Fix ansible-test python version usage.
* Fix ansible-test python version skipping.
* Use absolute path for log in ansible-test.
* Run vyos_command test on python 3.
* Fix windows/network instance persistence.
* Add `test/cache` dir to classification.
* Enable more python versions for network tests.
* Fix cs_router test.

test/runner/lib/sanity/rstcheck.py

@@ -15,6 +15,7 @@ from lib.util import (
     SubprocessError,
     run_command,
     parse_to_dict,
+    find_executable,
 )
 
 from lib.config import (
@@ -39,7 +40,8 @@ class RstcheckTest(SanitySingleVersion):
             return SanitySkipped(self.name)
 
         cmd = [
-            'rstcheck',
+            'python%s' % args.python_version,
+            find_executable('rstcheck'),
             '--report', 'warning',
             '--ignore-substitutions', ','.join(ignore_substitutions),
         ] + paths