Merge bitcoindevkit/bdk#1277: fix(readme): update examples

914db84824edf25418ab0b7b2df7bca84605d64d fix(readme): update examples (Jose Storopoli)

Pull request description:

  ### Description

  Some janitor cleaning in the README to update the `example-crates/`

  ### Notes to the reviewers

  None.

  ### Changelog notice

  - fix(readme): update example crates

  ### Checklists

  #### All Submissions:

  * [x] I've signed all my commits
  * [x] I followed the [contribution guidelines](https://github.com/bitcoindevkit/bdk/blob/master/CONTRIBUTING.md)
  * [x] I ran `cargo fmt` and `cargo clippy` before committing

  #### New Features:

  * [ ] I've added tests for the new feature
  * [ ] I've added docs for the new feature

  #### Bugfixes:

  * [ ] This pull request breaks the existing API
  * [ ] I've added tests to reproduce the issue which are now passing
  * [ ] I'm linking the issue being fixed by this PR

ACKs for top commit:
  danielabrozzoni:
    ACK 914db84824edf25418ab0b7b2df7bca84605d64d

Tree-SHA512: 9376e7ac816ebc4b0bd9652c2e357486e39c55f6542ef650087962b7a864655f7f70a6305b315363e3ed750ce4cea1a328b6a413c340aa94b693b130da2d36b5