Set minimum prompt_toolkit version to 3.0.28, because of cursor shape support.

Author: jonathanslenders

setup.py

@@ -21,8 +21,8 @@
         "appdirs",
         "importlib_metadata;python_version<'3.8'",
         "jedi>=0.16.0",
-        # Use prompt_toolkit 3.0.18, because of the `in_thread` option.
-        "prompt_toolkit>=3.0.18,<3.1.0",
+        # Use prompt_toolkit 3.0.28, because of cursor shape support.
+        "prompt_toolkit>=3.0.28,<3.1.0",
         "pygments",
     ],
     python_requires=">=3.7",