Add shell script to help build changelog

[thunderbiscuit]

This is just a small candy script. I don't even know if it needs to live in the repo, it's mainly to help maintainers build the changelog at every release.

Example

➜ bash parse-commits.sh "2025-03-01" "2025-04-01"

# Features
feat: add compact block filter client
feat: add proxy to electrum and esplora
feat: apply_unconfirmed_txs on wallet
feat: expose ElectrumClient::ping method
feat: migrate Amount to procedural macros
feat: migrate FeeRate to procedural macros

# Fixes
fix: broken links for bdk-jvm bdk-android maven central
fix: change Amount param to align with rust param
fix: export BumpFeeTxBuilder to uniffi

# Refactor
refactor: clean up our use of visibility qualifiers in tx_builder module
refactor: clean up visibility qualifiers in descriptor module
refactor: clean up visibility qualifiers in keys module
refactor: clean up visibility qualifiers in wallet module
refactor: migrate BumpFeeTxBuilder type to procedural macros
refactor: migrate TxBuilder type to procedural macros

# Chores
chore: build the release-smaller profile when using just command
chore: bump libraries to 1.2.0 development versions
chore: bump uniffi to 0.29.1
chore: remove readme warning
chore: remove unused JVM and Android dependencies

[rubensmachion]

Looks good to me!