build(deps): bump @polkadot/keyring in /integration-tests

Bumps [@polkadot/keyring](https://github.com/polkadot-js/common/tree/HEAD/packages/keyring) from 12.5.1 to 12.6.2.
- [Release notes](https://github.com/polkadot-js/common/releases)
- [Changelog](https://github.com/polkadot-js/common/blob/master/CHANGELOG.md)
- [Commits](https://github.com/polkadot-js/common/commits/v12.6.2/packages/keyring)

---
updated-dependencies:
- dependency-name: "@polkadot/keyring"
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

integration-tests/package.json

@@ -15,7 +15,7 @@
     "author": "",
     "license": "ISC",
     "dependencies": {
-        "@polkadot/keyring": "12.5.1",
+        "@polkadot/keyring": "12.6.2",
         "@types/ws": "^8.5.3",
         "axios": "^1.0.0",
         "creditcoin-js": "file:../creditcoin-js/creditcoin-js-v0.10.4.tgz",