Add/update SECURITY.md

Author: jaceklubzinski

SECURITY.md

@@ -1,2 +1,11 @@
 ## Reporting a Vulnerability
-Please report (suspected) security vulnerabilities in [GitHub issue](https://github.com/PiwikPRO/react-native-piwik-pro-sdk/issues). You will receive a response from us within 48 hours. If the issue is confirmed, we will release a patch as soon as possible depending on complexity but historically within a few days.
+
+If you discover a vulnerability in this repository, please use the **“Report a vulnerability”** feature available under the **Security** tab of the repository.  
+- Go to the repository on GitHub.  
+- Click on the **Security** tab.  
+- Select **Report a vulnerability** to securely notify us.  
+
+This ensures that sensitive information is not publicly disclosed before a fix is available.  
+
+## Response Timeline
+- You will receive an acknowledgment of your report within **48 hours**.