Merge bitcoindevkit/bdk#1999: fix(ci): pin `socket2@0.6.0` to `0.5.10` on MSRV

Merge bitcoindevkit/bdk#1999: fix(ci): pin `socket2@0.6.0` to `0.5.10` on MSRV

87399b117abf5130da236e47181d64a611138bf3 fix(ci): pin `socket2@0.6.0` to `0.5.10` (Leonardo Lima)

Pull request description:

  ### Description

  It pins the `socket2@0.6.0` to `0.5.10` in order to fix the MSRV CI step.

  ### Changelog notice

  - Update the `ci/pin-msrv.sh` to also pin `socket2@0.6.0` to `0.5.10` version.

  ### Checklists

  #### All Submissions:

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

ACKs for top commit:
  ValuedMammal:
    ACK 87399b117abf5130da236e47181d64a611138bf3
  LagginTimes:
    ACK 87399b117abf5130da236e47181d64a611138bf3

Tree-SHA512: 739345cdc7c6f51b77f9a6bcb9b8abafcb5bbec3142674f94eaa5394e9a83643de27cbc62e7962790352be17f7c4cc3812844054c7d01b129aace1bb100b3b97