The purpose of this referendum is to perform a runtime upgrade on Pendulum. The changes included are:

- Update Polkadot to version 0.9.42 
- Add treasury buyout extension pallet

For more details, please refer to the [GitHub release page](https://github.com/pendulum-chain/pendulum/releases/tag/pendulum-release-15).

Schedule a majority-carries referendum to be tabled next once it is legal to schedule
an external referendum.

The dispatch of this call must be `ExternalMajorityOrigin`.

- `proposal_hash`: The preimage hash of the proposal.

Unlike `external_propose`, blacklisting has no effect on this and it may replace a
pre-scheduled `external_propose` call.

Weight: `O(1)`

Authorize an upgrade to a given `code_hash` for the runtime. The runtime can be supplied
later.

The `check_version` parameter sets a boolean flag for whether or not the runtime's spec
version and name should be verified on upgrade. Since the authorization only has a hash,
it cannot actually perform the verification.

This call requires Root origin.

- **Problem Statement:** Upgrade Pendulum runtime by updating Polkadot to version 0.9.42 and adding a treasury buyout extension pallet.
- **Significance:** Enhancing Pendulum's functionality and compatibility with the latest Polkadot version.
- **Proposed Solution:** Perform a runtime upgrade on Pendulum.
- **Expected Outcomes:** Improved performance and compatibility with the latest Polkadot features.

#25 Authorize runtime upgrade for Pendulum release 15