Change CI to GitHub actions

Use copier template from oca/oca-addons-repo-template

Target Python3.7

Adapt modules to fix few issues

test_base_fileurl_field/__manifest__.py

@@ -6,6 +6,7 @@
     'version': '12.0.1.0.0',
     'category': 'Tests',
     'author': 'Camptocamp,Odoo Community Association (OCA)',
+    'website': 'https://github.com/camptocamp/odoo-cloud-platform',
     'license': 'AGPL-3',
     'depends': [
         'base_fileurl_field'

test_base_fileurl_field/tests/ir_attachment.py

@@ -14,9 +14,9 @@ class IrAttachment(models.Model):
     _inherit = "ir.attachment"
 
     def _get_stores(self):
-        l = ['s3']
-        l += super(IrAttachment, self)._get_stores()
-        return l
+        stores = ['s3']
+        stores += super(IrAttachment, self)._get_stores()
+        return stores
 
     @api.model
     def _store_file_read(self, fname, bin_size=False):