revert: Bump @modelcontextprotocol/inspector from 0.20.0 to 0.21.0

This reverts 2ebfcb4. `@modelcontextprotocol/inspector` requires Node.js version `>=22.7.5`

Author: flovogt

npm-shrinkwrap.json

@@ -98,7 +98,7 @@
 		"@eslint/js": "^9.39.2",
 		"@istanbuljs/esm-loader-hook": "^0.3.0",
 		"@istanbuljs/nyc-config-typescript": "^1.0.2",
-		"@modelcontextprotocol/inspector": "^0.21.0",
+		"@modelcontextprotocol/inspector": "^0.20.0",
 		"@stylistic/eslint-plugin": "^5.9.0",
 		"@types/ejs": "^3.1.5",
 		"@types/make-fetch-happen": "^10.0.4",