build(deps-dev): bump miniflare from 3.20230807.0 to 3.20230821.0

Bumps [miniflare](https://github.com/cloudflare/miniflare/tree/HEAD/packages/tre) from 3.20230807.0 to 3.20230821.0.
- [Release notes](https://github.com/cloudflare/miniflare/releases)
- [Commits](https://github.com/cloudflare/miniflare/commits/v3.20230821.0/packages/tre)

---
updated-dependencies:
- dependency-name: miniflare
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

package.json

@@ -67,7 +67,7 @@
     "eslint-plugin-jest": "^27.2.3",
     "eslint-plugin-prettier": "^4.2.1",
     "jest": "^29.6.2",
-    "miniflare": "^3.20230807.0",
+    "miniflare": "^3.20230821.0",
     "path-browserify": "1.0.1",
     "prettier": "^2.8.8",
     "process": "^0.11.10",