[PROPOSAL] Update Snapshot Quorum from 2.5M to 1.5M GTC

Summary

Update Snapshot Quorum from 2.5M to 1.5M GTC TL;DR This proposal lowers the quorum for Gitcoin DAO Snapshot votes from 2.5M GTC to 1.5M GTC. Background Gitcoin uses Snapshot for off-chain governance voting. Quorum is the minimum voting power that must take part for a proposal to be valid. The current quorum is 2.5M GTC. Rationale We are in the process of executing our governor upgrade on the Cactus platform, and our governance quorum should be mirrored on all voting platforms. Proposal here....