chore: update SDKs for appwrite 1.6.0

Author: christyjacob4

README.md

@@ -33,7 +33,7 @@ Add the package to your `Package.swift` dependencies:
 
 ```swift
     dependencies: [
-        .package(url: "git@github.com:appwrite/sdk-for-swift.git", from: "6.0.0-rc.3"),
+        .package(url: "git@github.com:appwrite/sdk-for-swift.git", from: "6.0.0"),
     ],
 ```
 

Sources/Appwrite/Client.swift

@@ -21,7 +21,7 @@ open class Client {
         "x-sdk-name": "Swift",
         "x-sdk-platform": "server",
         "x-sdk-language": "swift",
-        "x-sdk-version": "6.0.0-rc.3",
+        "x-sdk-version": "6.0.0",
         "x-appwrite-response-format": "1.6.0"
     ]