[wpe] Update to WPE WebKit 2.50.0

Even when this is an update to a new release series, there are no
differences from the packaging point of view, so the version number
change is enough.

Author: aperezdc

tools/scripts/bootstrap.py

@@ -81,7 +81,7 @@
 
 class Bootstrap:
     default_arch = "arm64"
-    default_version = "2.48.6"
+    default_version = "2.50.0"
 
     _cerbero_origin = "https://github.com/Igalia/wpe-android-cerbero.git"
     _cerbero_branch = "main"