[BIP-156] Authorize Migration to GaugeAdder v3

Motivation

As part of the coming migration to the Timelock Authorizer described in BIP-140 the Gauge Adder v2 also must undergo a migration to be compatible with the new authorizer.

The only differences from the old one is

• that it supports the new authorizer that we're migrating to (old one will break after migration)
• it allows multiple gauges per pool on ethereum mainnet now.

Specification

If approved, the DAO Multisig 0x10A19e7eE7d7F8a52822f6817de8ea18204F2e4f will initiate a transaction to interact with the Authorizer 0xA331D84eC860Bf466b4CdCcFb4aC09a1B43F3aE6 calling grantRole with the following arguments:

role: 0x0000000000000000000000000000000000000000000000000000000000000000

address: 0xE0f34c6AD719e6877062B7D97E12c61c096509AF

This can be verified here.

Additionally, the code for this migration can be viewed here.

In order to execute the migration, the DAO Multisig 0x10A19e7eE7d7F8a52822f6817de8ea18204F2e4f will initiate a transaction to interact with the GaugeAdderMigrationCoordinator 0xE0f34c6AD719e6877062B7D97E12c61c096509AF calling performNextStage()