chore: release 0.3.1

Fix a bug with the lockfile being out of date for 0.3.0 release.

Ref #207

chore: release 0.3

Includes one breaking change:

* Minimum nvim version is now 0.9

Other changes:

* `HANDLE_OPEN` flag for gtk (e.g. open files from GUI file managers)
* Popupmenu performance improvements

chore: release 0.2

New version and a brand new gnvim is here! Rewritten from the ground up
for gtk4, and now has:

* More complete and correct implementation of the ui api
* Custom rpc client
* Better code structure for easier development
* Updated UI
* Feature wise all the features are here.
* Rendering artefacts are now fixed, and the rendering performance should be
  better or at least on bar compared to the previous version.

Move redraw event handlers into their own functions

Merge pull request #68 from smolck/silence-warnings

Fix a few minor issues (compiler warnings)

Remove 'help-circle.svg' (question mark) icon from unknown autocomple…

…tions (#50)

* remove 'help-circle' icon for unknown completion items in popupmenu

* Remove unnecessary comments

* Remove (more) unnecessary comments

* This commit changes the behavior of unknown completions.

Unknown completions in the pmenu now show icons if one or more completions' kinds in the pmenu are known (to gnvim). This is done by iterating throughout the items in the pmenu when necessary to check if their completion kind is known (to gnvim).

* Refactor previous changes

Some notable changes in this commit include the additoin of the
'CompletionItemKind' enum to nvim_bridge.rs per vhakulinen's
suggestion, in addition to changing the 'CompletionItemWidgetWrap::create'
function to take a reference to the other items in the popupmenu.
That function then checks whether or not any other items in the
pmenu have icons to determine if it should use an icon
for the created 'CompletionItemWidgetWrap' object if it's kind is
unknown.

I have also refactored `get_icon_pixbuf` and `get_icon_name_for_kind`
to take a reference to a 'CompletionItemKind' instead of a 'str'.

* Refactor to use  variable

* Refactor to use `show_kind` variable

* Refactor with changes requested by @vhakulinen

* Add less padding when all completion items are unknown.

* Avoid unnecessary clone

* Add padding to `info` when kind is not shown

Merge pull request #45 from elihunter173/master

Improve .desktop file

Close #11

Remove -v flags from `install` in makefile

Note about version to readme