Add disclaimer to not use Masterkey on client side (#474)

* Add disclaimer to not use Masterkey on client side

Author: nstrelow

packages/dart/README.md

@@ -57,7 +57,7 @@ It's possible to add other parameters to work with your instance of Parse Server
         securityContext: securityContext, // Again, required for some setups
 	coreStore: CoreStoreMemoryImp()); // Non persistent mode (default): Sdk will store everything in memmore instead of using Sembast as an internal DB.
 ```
-
+⚠️ Please note that the master key should only be used in safe environments and never on client side ‼️ Using this package on a server should be fine.
 
 #### Early Web support
 Currently this requires adding `X-Parse-Installation-Id` as an allowed header to parse-server.

packages/flutter/README.md

@@ -52,6 +52,7 @@ It's possible to add other parameters to work with your instance of Parse Server
 	coreStore: await CoreStoreSharedPrefsImp.getInstance()); // Local data storage method. Will use SharedPreferences instead of Sembast as an internal DB
 ```
 
+⚠️ Please note that the master key should only be used in safe environments and never on client side ‼️
 
 #### Web support
 Due to Cross-origin resource sharing (CORS) restrictions, this requires adding `X-Parse-Installation-Id` as an allowed header to parse-server.