Param

Minor release for Panel-related bugfixes and minor features, from philippjfr.

- Fix serialization of Tuple, for use in Panel ([446](https://github.com/holoviz/param/pull/446))
- Declare asynchronous executor for Panel to use ([449](https://github.com/holoviz/param/pull/449))
- Switch to GitHub Actions ([450](https://github.com/holoviz/param/pull/450))

- Fixed ClassSelector.get_range when a tuple of types is supplied ([360](https://github.com/holoviz/param/pull/360))

- Compatibility with Python 3.8
- Add eager option to watch calls ([351](https://github.com/holoviz/param/pull/351))
- Add Calendar and CalendarDateRange for real date types ([348](https://github.com/holoviz/param/pull/348))

Enhancements:

- Allow param.depends to annotate functions ([334](https://github.com/holoviz/param/pull/334))
- Add context managers to manage events and edit constant parameters

Bug fixes:

- Ensure that Select constructor does not rely on truthiness ([337](https://github.com/holoviz/param/pull/337))
- Ensure that param.depends allows mixed Parameter types ([338](https://github.com/holoviz/param/pull/338))
- Date and DateRange now allow dt.date type ([341](https://github.com/holoviz/param/pull/341))
- Ensure events aren't dropped in batched mode ([343](https://github.com/holoviz/param/pull/343))

Full release with new functionality and some fixes. New features:

- Added support for instance parameters, allowing parameter metadata to be modified per instance and allowing parameter objects to be passed to Panel objects ([306](https://github.com/holoviz/param/pull/306))
- Added label slot to Parameter, to allow overriding attribute name for display ([319](https://github.com/holoviz/param/pull/319))
- Added step slot to Parameter, e.g. to control Panel widget step size ([326](https://github.com/holoviz/param/pull/326))
- Added keywords_to_params utility for deducing Parameter types and ranges automatically ([317](https://github.com/holoviz/param/pull/317))
- Added support for multiple outputs from a Parameterized ([312](https://github.com/holoviz/param/pull/312))
- Added Selector as a more user-friendly version of ObjectSelector, accepting a list of options as a positional argument ([316](https://github.com/holoviz/param/pull/316))

Changes affecting backwards compatibility:

- Changed from root logger to a param-specific logger; no change to API but will change format of error and warning messages ([330](https://github.com/holoviz/param/pull/330))
- Old abstract class Selector renamed to SelectorBase; should be no change unless user code added custom classes inherited from Selector without providing a constructor ([316](https://github.com/holoviz/param/pull/316))

Bugfixes and other improvements:

- Various bugfixes ([320](https://github.com/holoviz/param/pull/320), [#323](https://github.com/holoviz/param/pull/323), [#327](https://github.com/holoviz/param/pull/327), [#329](https://github.com/holoviz/param/pull/329))
- Other improvements ([315](https://github.com/holoviz/param/pull/315), [#325](https://github.com/holoviz/param/pull/325))

For more details, you can see a [full list of changes since the previous release](https://github.com/holoviz/param/compare/v1.8.2...v1.9.0).