[stubsabot] Bump docutils to 0.21.*

Release: https://pypi.org/pypi/docutils/0.21.1
Homepage: https://docutils.sourceforge.io
Repository: https://sourceforge.net/p/docutils/code
Typeshed stubs: https://github.com/python/typeshed/tree/main/docutils

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- Leave this PR open (as a reminder, and to prevent stubsabot from opening another PR)
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stubs/docutils/METADATA.toml

@@ -1,4 +1,4 @@
-version = "0.20.*"
+version = "0.21.*"
 upstream_repository = "https://sourceforge.net/p/docutils/code"
 partial_stub = true