Merge bitcoindevkit/bdk#1782: fix electrum conftime_req filter for needs_block_height

20100aabd54d507e01894993829b2968cee10f25 ci: downgrade all workflows to ubuntu to 20.04 (Steve Myers)
53fb49fd009d8634f96a231a29394c64aa93bf9c ci(clippy): fix disallow ref to static mut (Steve Myers)
f2e163206483dd0a6d19f339247ea963c64f4824 ci: pin msrv dep version for ureq (Steve Myers)
fa53884d214f47d5f64a95e5e1282b3bbfc3aca5 ci: pin msrv dep version for rustls and hashbrown (Steve Myers)
6a5b418f6c88127bd9af22f18d859bafd6403d8c ci(clippy): fix missing docs errors for rust 1.83 (Steve Myers)
341b86986bbc3f57264d658b3343fd714d6ecbe3 ci(clippy): fix updated ptr_arg check for rust 1.83 (Steve Myers)
24ec31bf66ec3a3788f96e8941c203a1e198af81 ci(clippy): fix new stricter needless_lifetime errors for rust 1.83 (Steve Myers)
4aa8fba7f0005f27bc4d581891535dabd426ac0c ci: update examples/rpcwallet to use electrds/bitcoind_22_1 (Steve Myers)
8d190bacedf80039626397ba87d5b7139cb644e6 fix electrum conftime_req filter for needs_block_height (Zoe Faltibà)

Pull request description:

  <!-- You can erase any parts of this template not applicable to your Pull Request. -->

  ### Description

  <!-- Describe the purpose of this PR, what's being adding and/or fixed -->

  This PR fixes a bug introduced in https://github.com/bitcoindevkit/bdk/commit/04994e4f7f1073e7bef29528339369994d4b3666#diff-57bf66f87897e694c5ebfdfe0fd366774dda30b43eab93c1a0fdc802d0eb8c8dR171

  In that commit `block_times.get(height).is_none()` was converted to `block_times.contains_key(height)`, inverting the code logic.

  ### 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

ACKs for top commit:
  notmandatory:
    ACK 20100aabd54d507e01894993829b2968cee10f25
  oleonardolima:
    utACK 20100aabd54d507e01894993829b2968cee10f25
  nymius:
    ACK 20100aabd54d507e01894993829b2968cee10f25

Tree-SHA512: 85b41b4f00273d0936172d7b845d28343b519cf698b4127dba85d45ab4030c69b6696f029bec38a58e3c2b3b17ff77620970d4c8fe20529980b13082299f5241