Merge bitcoindevkit/bdk#1087: ci: fix msrv dependency versions for reqest and h2

4f37b2a293df57cdc7c4bae7d4ae8e0f04dd8032 ci: fix msrv dependency versions for reqest and h2 (Steve Myers)

Pull request description:

  ### Description

  Fix MSRV dependency versions for `reqwest` and`h2`, both latest version now require 1.63.0.

  ### Notes to the reviewers

  - reqwest 0.11.19 has MSRV 1.63.0+, pin to 0.11.18
  - h2 0.3.21 has MSRV 1.63.0+, pin to 0.3.20

  ### Changelog notice

  None.

  ### 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:
  danielabrozzoni:
    ACK 4f37b2a293df57cdc7c4bae7d4ae8e0f04dd8032

Tree-SHA512: 6cc5bdc793d57f8b28d10f70041c1faae686da95182e313c3c854d9d58f003a75a381f2e5ca660c9eb41356937197e9f84bc756695e06b3718e281d3e818af51