ci: shift cdist-group-steal to 2:10

Match the fix landing in concurrent clientless-* PRs (#134, #135, #136,
#137, #138). pytest-cdist 0.3.x accepts only one steal entry, and 3:10
leaves the middle shard empty when file justification moves a large
test file across the chunk boundary, failing CI.

Author: cofin

pyproject.toml

@@ -385,7 +385,9 @@ line-length = 120
 
 [tool.pytest.ini_options]
 addopts = "--doctest-glob='*.md' --dist=loadgroup"
-cdist-group-steal = "3:10"
+# Keep the middle shard non-empty when file justification moves a large test file
+# across cdist chunk boundaries. pytest-cdist 0.3.x accepts only one steal entry.
+cdist-group-steal = "2:10"
 cdist-justify-items = "file"
 filterwarnings = [
   "ignore::DeprecationWarning:pkg_resources",