[FIX] event: QR code is squished

Current behaviour:
QR code is squished, it's 77x21 px

Expected behaviour:
QR code should be 100x100 px

Steps to reproduce:
1. Go Email Templates
2. Find 'Event: Registration Confirmation'
3. Click on preview
4. QR code is squished

opw-3625701

closes odoo/odoo#145963

Signed-off-by: Jérémy Hennecart (jeh) <jeh@odoo.com>

addons/event/data/mail_template_data.xml

@@ -269,7 +269,7 @@
                     </div>
                     <t t-if="object.barcode"> 
                         <div style="margin-bottom: 5px;">
-                            <img t-attf-src="/report/barcode/QR/{{object.barcode}}?&amp;width=100&amp;height=100&amp;quiet=0" alt="QR Code"/>
+                            <img t-attf-src="/report/barcode/QR/{{object.barcode}}?&amp;width=100&amp;height=100&amp;quiet=0" width="100" height="100" alt="QR Code"/>
                         </div>
                     </t>
                     <t t-if="not object.company_id.uses_default_logo">