Bump immer from 9.0.19 to 9.0.21

Bumps [immer](https://github.com/immerjs/immer) from 9.0.19 to 9.0.21.
- [Release notes](https://github.com/immerjs/immer/releases)
- [Commits](https://github.com/immerjs/immer/compare/v9.0.19...v9.0.21)

---
updated-dependencies:
- dependency-name: immer
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

packages/core/package.json

@@ -141,7 +141,7 @@
     "history": "^4.10.1",
     "hpagent": "^1.2.0",
     "http-proxy": "^1.18.1",
-    "immer": "^9.0.19",
+    "immer": "^9.0.21",
     "joi": "^17.9.1",
     "js-yaml": "^4.1.0",
     "lodash": "^4.17.15",