Add tagbar plugin

[dxm1337]

This is a

• New plugin.
• Update to an existing plugin.

Plugin name and version:
Name: tagbar
version 0.1.0

Plugin source code zip file: https://github.com/dxm1337/tagbar/releases/download/v0.1.0/tagbar-0.1.0.zip

Checklist:

• Plugin has a repo.json listing the Name, Description, Website, and License.
• I have read the instructions at https://github.com/micro-editor/plugin-channel#adding-your-own-plugin.