Update comment on the top

Author: sajith

.github/workflows/build.yml

@@ -1,5 +1,11 @@
-# Build sdist+wheel packages using GitHub Actions.  Mostly adopted
-# from https://cibuildwheel.readthedocs.io/en/stable/setup/
+# Build sdist+wheel packages using GitHub Actions, and publish them on
+# TestPyPI (on pull requests and tags) and PyPI (on tags).
+#
+# The build_wheels job is mostly adopted from
+# https://cibuildwheel.readthedocs.io/en/stable/setup/
+#
+# The upload_pypi and upload_testpypi jobs are adopted from Python
+# Packaging User Guide.
 
 name: "Packages"