1. Open a PR on Nixpkgs merging `haskell-updates` into `master`.
Use the following message body:
```markdown
### This Merge
This PR is the regularly merge of the `haskell-updates` branch into `master`.
This branch is being continually built and tested by hydra at https://hydra.nixos.org/jobset/nixpkgs/haskell-updates.
I will aim to merge this PR **by 2021-TODO-TODO**. If I can merge it earlier, there might be successor PRs in that time window. As part of our rotation @TODO will continue these merges from 2021-TODO-TODO to 2021-TODO-TODO.
### haskellPackages Workflow Summary
Our workflow is currently described at `pkgs/development/haskell-modules/HACKING.md`.
The short version is this:
* We regularly update the stackage and hackage pins on `haskell-updates` (normally at the beginning of a merge window).
* The community fixes builds of Haskell packages on that branch.
* We aim at at least one merge of `haskell-updates` into `master` every two weeks.
* We only do the merge if the `mergeable` job is succeeding on hydra.
* If a maintained package is still broken at the time of merge, we will only merge if the maintainer has been pinged 7 days in advance. (If you care about a Haskell package, become a maintainer!)
---
This is the follow-up to #TODO.
```
Make sure to replace all TODO with the actual values.