[SPARK-52123] Add Resources section

### What changes were proposed in this pull request?

This PR aims to add `Resources` section to `README.md` file.

### Why are the changes needed?

This section will help to visit various web resources easily.

- Homepage
  <img width="830" alt="Screenshot 2025-05-13 at 20 08 07" src="https://github.com/user-attachments/assets/2090eea8-4761-4363-9486-188f0e3dba96" />

- Swift Package Index
  <img width="826" alt="Screenshot 2025-05-13 at 20 08 57" src="https://github.com/user-attachments/assets/cc1cc177-8a8b-4d64-8841-0c105385bbde" />

- Library Documentation
  <img width="1030" alt="Screenshot 2025-05-13 at 20 09 58" src="https://github.com/user-attachments/assets/e6a348fc-469d-4d5d-8c8b-ab4e346fc3f3" />

### Does this PR introduce _any_ user-facing change?

No behavior change.

### How was this patch tested?

Manual review by visiting the web resources.

### Was this patch authored or co-authored using generative AI tooling?

No.

Closes #145 from dongjoon-hyun/SPARK-52123.

Authored-by: Dongjoon Hyun <[email protected]>
Signed-off-by: Dongjoon Hyun <[email protected]>

Author: dongjoon-hyun

README.md

@@ -8,6 +8,12 @@ This is an experimental Swift library to show how to connect to a remote Apache
 
 So far, this library project is tracking the upstream changes like the [Apache Spark](https://spark.apache.org) 4.0.0 RC6 release and [Apache Arrow](https://arrow.apache.org) project's Swift-support.
 
+## Resources
+
+- [Homepage](https://apache.github.io/spark-connect-swift/)
+- [Swift Package Index](https://swiftpackageindex.com/apache/spark-connect-swift/)
+- [Library Documentation](https://swiftpackageindex.com/apache/spark-connect-swift/main/documentation/sparkconnect)
+
 ## Requirement
 
 - [Apache Spark 4.0.0 RC6 (May 2025)](https://dist.apache.org/repos/dist/dev/spark/v4.0.0-rc6-bin/)