message: Update link to council snapshot in mainnet.md
diff: @@ -103,4 +103,4 @@ upgrade window: 720
  | ipfs.cat in mappings | | Yes | Yes | No | No | No |
  | ENS | | Yes | Yes | No | No | No |
  -[Council snapshot](https://snapshot.org/#/council.graphprotocol.eth/proposal/0xbdd884654a393620a7e8665b4289201b7542c3ee62becfad133e951b0c408444)
  +[Council snapshot](https://snapshot.org/#/council.graphprotocol.eth/proposal/0x4fa76f9ae541bf883e547407270866ffeb8448f3b3fca90bb9c5bc46e31499c2)
  