Merge #1876: ci: pin ring to 0.17.12 for MSRV 1.63

7d4128e ci: pin ring dep to 0.17.12 to fix MSRV (Steve Myers)

Pull request description:

  ### Description

  Pin `ring` to `0.17.12` for MSRV.

  ### 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 7d4128e

Tree-SHA512: c210e511955734d3c513a020ea0b7596590b048d755c026aa508f83e43ac2e2f25064a5fea1aa0e343e80b5c03bf8b52aa370dcbd708251197ca6788dac8bd66

Author: evanlinjin

ci/pin-msrv.sh

@@ -24,3 +24,4 @@ cargo update -p unicode-width --precise "0.1.13"
 cargo update -p native-tls --precise "0.2.13"
 cargo update -p flate2 --precise "1.0.35"
 cargo update -p bzip2-sys --precise "0.1.12"
+cargo update -p ring --precise "0.17.12"