Add symfony/scaleway-mailer recipe (#1226)

Author: MrMicky-FR

symfony/scaleway-mailer/6.4/manifest.json

@@ -0,0 +1,6 @@
+{
+    "env": {
+        "#1": "MAILER_DSN=scaleway+api://PROJECT_ID:API_KEY@default",
+        "#2": "MAILER_DSN=scaleway+smtp://PROJECT_ID:API_KEY@default"
+    }
+}