android: set target_sdk_version to 34

To comply with new google play store requirement:

> Starting August 31 2024:
> - New apps and app updates must target Android 14 (API level 34) or higher to be submitted to Google Play

AFAICS, we do not need to adapt to any of the changes.
https://developer.android.com/about/versions/14/behavior-changes-14

contrib/android/buildozer_qml.spec

@@ -89,7 +89,7 @@ android.permissions = INTERNET, CAMERA, WRITE_EXTERNAL_STORAGE
 android.api = 31
 
 # (int) Android targetSdkVersion
-android.target_sdk_version = 33
+android.target_sdk_version = 34
 
 # (int) Minimum API required. You will need to set the android.ndk_api to be as low as this value.
 android.minapi = 23