[MINOR] Add compatibility badges

Author: dongjoon-hyun

README.md

@@ -1,6 +1,8 @@
 # Apache Spark Connect Client for Swift
 
 [![GitHub Actions Build](https://github.com/apache/spark-connect-swift/actions/workflows/build_and_test.yml/badge.svg)](https://github.com/apache/spark-connect-swift/blob/main/.github/workflows/build_and_test.yml)
+[![Swift Version Compatibility](https://img.shields.io/endpoint?url=https%3A%2F%2Fswiftpackageindex.com%2Fapi%2Fpackages%2Fapache%2Fspark-connect-swift%2Fbadge%3Ftype%3Dswift-versions)](https://swiftpackageindex.com/apache/spark-connect-swift)
+[![Platform Compatibility](https://img.shields.io/endpoint?url=https%3A%2F%2Fswiftpackageindex.com%2Fapi%2Fpackages%2Fapache%2Fspark-connect-swift%2Fbadge%3Ftype%3Dplatforms)](https://swiftpackageindex.com/apache/spark-connect-swift)
 
 This is an experimental Swift library to show how to connect to a remote Apache Spark Connect Server and run SQL statements to manipulate remote data.