Streamlit-code-editor

- fixed performance issue where custom streamlit themes load slowly
compared to default theme resulting in a flicker between the two on initial render
- fixed issue where height of component is changed twice sequentially on initial render
when it should only happen once.

- added support for changing code contents while key argument is unchanged.
This involves a new prop called `allow_reset` which resets the editor contents to the input code

NEW FEATURES
- `selected` property added to response dictionary. This property will contain the portion of the code that is selected/highlighted
- `response_mode` argument added to `code_editor` function. This argument takes a single string or an array of multiple string values. The currently accepted values are: `"default"`, `"debounce"`, `"blur"`, `"select"`.
- `"default"` - the code editor only returns a response if a response command is called
- `"debounce"` - the code editor returns a response when a fixed amount of time has passed after the last change made to the contents of the editor. If another change is made before the time is up, then the timer is reset and restarted. This amount of time can be set using the `debounceChangePeriod` prop which defaults to `250` ms.
- `"blur"` - the code editor returns a response when focus leaves the editor.
- `"select"` - the code editor returns a response when the text selection changes.

BUG FIXES
- fixed issue where custom commands get removed after reruns/rerenders
- reduced `react-script` related errors in build

This release has
- Improved loading of default themes
- performance improvements
- bug fixes