chore: fix redis param name in GenericProcessorSnapshot

[xadahiya]

Fixes #85

Checklist

• My branch is up-to-date with upstream/develop branch.
• Everything works and tested for Python 3.8.0 and above.
• I ran pre-commit checks against my changes.

Changes

Update GenericProcessorSnapshot definition to

    @abstractmethod
    async def compute(
        self,
        epoch: PowerloomSnapshotProcessMessage,
        redis_conn: aioredis.Redis,
        rpc_helper: RpcHelper,
    ):
        pass

[anomit]

LGTM