fix: upgrade action runtime from node20 to node22

GitHub is deprecating Node.js 20 for GitHub Actions, producing
warning annotations in consuming workflows.

Ticket: CTX-144

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: ericcrosson-bitgo

action.yml

@@ -21,5 +21,5 @@ inputs:
     default: false
 
 runs:
-  using: node20
+  using: node22
   main: dist/index.js