Describe the bug

With the updated 1.10.2 gh cli we are seeing a GraphQL error when trying to merge PRs against our GHE instance. If we revert gh back to 1.9.2 everything is working fine

We tested other gh pr commands with 1.10.2 and those seemed to work fine (checks, close, comment, create, diff, list, ready, reopen, review, status, view). Seems like the issue is just with gh pr merge

Current Versions:
gh version 1.10.2 (2021-05-19)
Github Enterprise Server version: v2.21.19

Note: we don't see the issue when reverting gh back to 1.9.2

Steps to reproduce the behavior

1. Configure gh cli with Github Enterprise instance
2. Run gh pr merge <redacted PR url> --delete-branch --merge
3. See GraphQL error

Expected vs actual behavior

Expected: no error and PR is merged and branch deleted
Actual: GraphQL Error

Logs

[2021-05-21T10:18:54.902Z] + gh pr merge <redacted PR url> --delete-branch --merge
[2021-05-21T10:18:55.166Z] GraphQL error: Field 'authors' doesn't exist on type 'Commit'
script returned exit code 1