The minimum supported Rust version was bumped the 1.48, the current
version of rustc on Debian stable.

Features:
- The number of stakeholders and managers is now limited to 20
- Multi-Cancel with static fee-bumping support

Fixes:
- Detection of the CPFP output in an Unvault or a Spend
transaction

An updated release for the third demo of Revault. Notable changes since
the 4.0 release include the CPFP transaction management.

Features:

• The CPFP descriptor creation was modified to not be compiled from a
  Miniscript policy but instead always use the multi() legacy
  descriptor
• CPFP transaction creation from Spend and Unvault CPFP outputs,
  feerate computation and basic coin selection.

A new release for the third demo of Revault. Notable changes include
making PSBTs compatible with external signers and removing mutable
access API to prevent any way to break internally assumed invariants.

Features:

• A new keys method was added to derived descriptors, analog to the xpubs method of
  generalistic descriptors
• Key source info was added to derived descriptors
• BIP32 derivation paths were added to PSBT inputs and outputs
• SpendTxOut is no longer an enum, just a new type over bitcoin's TxOut
• We don't expose mutable access to inner PSBT in transaction newtypes anymore
• The Emergency transaction pre-signed feerate was increased
• Specifying Cosigning Servers keys is now optional for UnvaultDescriptor and DerivedUnvaultDescriptor

Fixes:

• We now check for duplicated input when creating a SpendTransaction
• We now sanity check the amount in the PSBT input of revocation transactions

This new release in view of the release of a second demo of Revault was
marked with the introduction of an MSRV (1.43), several API improvements
and bug fixes.

Features

• add_signature now checks the signature validity
• Transaction outputs are now differentiated by being either internal
  (we now their witness script) or external.
• The signature hash methods have been deduplicated into a single
  signature_hash().
• A cached version of signature_hash was added.
• We now use the Amount type when manipulating/returning amounts.
• Misc API improvements to the RevaultTransaction trait.
• A new managers_threshold method was added to get the minimum number
  of managers' signatures required to satisfy the UnvaultDescriptor.
• We now commit to a MSRV: 1.43.

Fixes

• More parsing checks uncovered by fuzzing
• We now refuse to create dust outputs in the Spend transaction
• We now sanity check the amount of outputs

This is an alpha release containing a subset of the expected features in
order to be able to test an excerpt of Revault's features in a demo
deployment.