`docs.py` is broken on CI

[keighrim]

build_versioned_docs() in build-tools/docs.py calls python setup.py develop against the checked-out source tree:

Howevr, since 1.4.0 dropped setup.py in favor of pyproject.toml. The publish workflow now fails at the docs-publish step on every release going forward.

PR #381 (clams-vocabulary and pyproject.toml migration) updated build_docs_local() to use pip install -e .[docs] but left build_versioned_docs() calling the legacy setup.py develop. The two install paths live in the same file and were updated piecemeal.

Fix

• manually build 1.4.0 document and upload to the documentation hub repo
• fix docs.py Easy fix will be check for existence of setup.py before building a versioned docs. This should keep the legacy path so historical-version docs rebuilds still work