Update sentry-android-gradle-plugin version to 6.0.0-rc.1

Updated the minimum required version for build distribution and size analysis from 6.0.0-beta1 to 6.0.0-rc.1.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: runningcode

src/components/gradleUploadInstructions.tsx

@@ -27,7 +27,7 @@ export function GradleUploadInstructions({feature}: Props) {
           <a href="/platforms/android/configuration/gradle/">
             Sentry Android Gradle plugin
           </a>{' '}
-          with at least version <code>6.0.0-beta1</code>
+          with at least version <code>6.0.0-rc.1</code>
         </li>
 
         <li>