Add HAL plugin to Snapshot

TLDR

• Snapshot recently added a HAL plugin (hal.xyz)
• The plugin allows users to receive notifications every time a new proposal is created or ends

More information on https://medium.com/@HALxyz/tutorial-how-to-set-up-hal-snapshot-plugin-a3a86e818dd6

FOR

Add HAL plugin to Snapshot.

AGAINST

Don’t add the HAL plugin.