Add Google mailer

SMTP is the default provider to send email.
But users tend to use Gmail from time to time. So, instead of a complex installation to allow it, we prefer to ship it with the default package.

Also:
- update deps globally
- lock symfony/* deps to 4.4

.github/workflows/assets.yml

@@ -5,7 +5,7 @@ on:
   push:
     branches:
       - master
-      - 2.*
+      - "2.**"
 
 permissions:
   contents: read

.github/workflows/coding-standards.yml

@@ -5,7 +5,7 @@ on:
   push:
     branches:
       - master
-      - 2.*
+      - "2.**"
 
 permissions:
   contents: read

.github/workflows/continuous-integration.yml

@@ -5,7 +5,7 @@ on:
   push:
     branches:
       - master
-      - 2.*
+      - "2.**"
 
 env:
   PGPASSWORD: wallabagrocks

.github/workflows/translations.yml

@@ -5,7 +5,7 @@ on:
   push:
     branches:
       - master
-      - 2.*
+      - "2.**"
 
 permissions:
   contents: read