Bump MU_BASECORE from e1eb585 to a961222 (#1278)

Bumps [MU_BASECORE](https://github.com/microsoft/mu_basecore) from `e1eb585` to `a961222`.
- [Release notes](https://github.com/microsoft/mu_basecore/releases)
- [Commits](microsoft/mu_basecore@e1eb585...a961222)

---
updated-dependencies:
- dependency-name: MU_BASECORE
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>