Update Android baseline in README.md

* minimum NDK is 23 since
  Change-Id I9ea714255faf29d50bb5f8e206f13495637da867
  ("android: Require NDK 23 and use default linker lld");
  TDF Jenkins uses NDK 25.

* Gradle plugin 7.4.0 used since
  commit 20989728c7
  ("android: Update Android Gradle Plugin to 7.4.0")
  has minimum and default SDK version 30.0.3 [1].

[1] https://developer.android.com/studio/releases/gradle-plugin#7-4-0

Change-Id: I9d8f09b21f5ffbee4f3cc9dd7bcc7770031cec65
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/146243
Tested-by: Jenkins
Reviewed-by: Michael Weghorn <m.weghorn@posteo.de>

README.md

@@ -47,7 +47,7 @@ run and compile LibreOffice, also used by the TDF builds:
     * Runtime: 11.4 (only support for newer i devices == 64 bit)
     * Build: Xcode 9.3 and iPhone SDK 11.4
 * Android:
-    * Build: NDK r19c and SDK 22.6.2
+    * Build: NDK r23 and SDK 30.0.3
 * Emscripten / WASM:
     * Runtime: a browser with SharedMemory support (threads + atomics)
     * Build: Qt 5.15 with Qt supported Emscripten 1.39.8