GIP-0052: Timeline and requirements to increase rewards in L2

I’ve PRd an update to the dates in the GIP here: GIP-0052: update dates by pcarranzav · Pull Request #31 · graphprotocol/graph-improvement-proposals · GitHub - it now reflects the dates when the 25% and 50% increases happened, and has updated estimates for when the next increases could happen.

I’ve also edited the OP to only show Abstract and Motivation here and link to the full text on GitHub, like we’ve done for other GIPs recently; this makes it easier to keep the latest version in a single place.