Merge bitcoindevkit/bdk#659: Fix: Run README.md examples on the CI

9d2024434eb0d542133d06db14020968e713fd9b Fix: Run README.md example on the CI (meryacine)

Pull request description:

  ### Description
  Seems like `doc(include = "../README.md")` doesn't include the readme file as doc for the dummy struct. This might be due to a difference in Rust edition used back then or something.

  Fixes #637
  ### 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

  #### Bugfixes:

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

ACKs for top commit:
  danielabrozzoni:
    tACK 9d2024434eb0d542133d06db14020968e713fd9b

Tree-SHA512: 5842f7cdc34d76045596a248ec80bbcf86591ec9abe32d92af8322672e7a5d08d3b4baf1a000b1556542b449271dc8c438e6269eaf0204bee815c67fcf1218a8