Downgrade twine

The current version (3.2.0) installation misses two dependencies when using conda to install it.

As requested by @amohammadi, downgrade to a version that does not have that issue.

conda/meta.yaml

@@ -43,7 +43,7 @@ requirements:
     - requests
     - sphinx
     - pyyaml >=5.1
-    - twine
+    - twine <3
     - lxml
     - jinja2
     - termcolor