Merge bitcoindevkit/bdk#2166: fix(ci): pin required `icu_*` deps for 1.85.0

cc7cac95dd5f88510b578cf88ae894199cf9183b fix(ci): pin required `icu_*` deps for 1.85.0 (Leonardo Lima)

Pull request description:

  ### Description

  It fixes the 1.85.0 MSRV CI step, by pinning the following:

  - icu_normalizer to "2.1.1"
  - icu_provider to "2.1.1"
  - icu_locale_core to "2.1.1"

  ### Changelog notice

  ```
  ### Changed

  - fix(ci): pin required `icu_*` dependencies for 1.85.0 supported MSRV.

  ```

  ### Checklists

  #### All Submissions:

  * [x] I followed the [contribution guidelines](https://github.com/bitcoindevkit/bdk/blob/master/CONTRIBUTING.md)

ACKs for top commit:
  luisschwab:
    ACK cc7cac95dd5f88510b578cf88ae894199cf9183b

Tree-SHA512: 707a6ca21662fd63a7f8896e55d763df2c006baf3efb2759abf64eb0414d4d3cdcadbb054d88104f270eb3987cb1c90ae5a5e18707ef426b8ecefe6b569d16e2