Semgrep issues fixed, README.md update

chore: package dependency versions updated to fix semgrep issues in testPlugin
feat: README.md includes installation guide for v6, v5 and v4

Author: vivekshindhe

README.md

@@ -23,8 +23,15 @@ Capacitor plugin to support [Razorpay Standard Checkout](https://developer.apple
 
 ## Installation
 
+### Capacitor v6:
 - `npm i -S https://github.com/razorpay/razorpay-capacitor.git`
 
+### Capacitor v5:
+- `npm i -S https://github.com/razorpay/razorpay-capacitor.git#76fd7d6b59f631eb44e6ecebc9188b2425168beb`
+
+### Capacitor v4:
+- `npm i -S https://github.com/razorpay/razorpay-capacitor.git#8faf4530bd5a701af190e64ac406ddb3ed2b1d2e`
+
 ## Adding Plugin For Android Integration
 
 Add the Checkout class to the ArrayList in the MainActivity class in {{projectDir}}/android/src/main/MainActivity.java