Update boltz-client to v2.3.4

[jackstar12]

No description provided.

[nmfretz]

Thanks for this update @jackstar12. I have tested and it is working well.

We need to update the app manifest (umbrel-app.yml) in order for users to receive an update notification in umbrelOS.

I can't push to your fork:

$ git push BoltzExchange HEAD:update-boltz-client
remote: Permission to BoltzExchange/umbrel-apps.git denied to nmfretz.

So can you please make the following changes to the manifest:

1. Update version to something like "0.15.4-beta-boltz"

2. Add release notes. Feel free to just copy this:

releaseNotes: >-
  This release updates the Boltz Client that runs alongside Ride The Lightning to version 2.3.4.
  The main change is improved transaction broadcasting.


  Full release notes for Boltz Client can be found at https://github.com/BoltzExchange/boltz-client/releases

  
  Full release notes can be found at https://github.com/Ride-The-Lightning/RTL/releases

The strange looking spacing in the release notes is needed for proper rendering in the app store UI.

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[jackstar12]

@nmfretz done. Will update the manifest rightaway next time

[nmfretz]

Wonderful, thanks @jackstar12!

Will update the manifest rightaway next time

If you feel comfortable with it please feel free to just give me push access to your fork of this repo and then I can make small tweaks without you needing to do them. Totally up to you though.