[FIX] website_pre_loader_style: Warning raised by typo in manifest key: "license"

The word 'license' can be written "licence" too but odoo expects
"license".

The fallowing warning was being raised, even when the module was not
installed.

WARNING ? odoo.modules.module: Missing `license` key in manifest for
'website_pre_loader_style', defaulting to LGPL

website_pre_loader_style/__manifest__.py

@@ -47,7 +47,7 @@
         ]
     },
     'images': ['static/description/banner.jpg'],
-    'licence': 'AGPL-3',
+    'license': 'AGPL-3',
     'installable': True,
     'auto_install': False,
     'application': False,