Update to 0.28.0.

Changelog:

• Added --header-first option to print header before the prompt line
• Added --scroll-off=LINES option (similar to scrolloff option of Vim)
• Fixed bug where preview window is not updated on reload

Packaging:

• Add the vim plugin to neovim's runtime path

• Used it to search for files interactively
• Tested the functionality of vim plugin in neovim