Set up trigger for deploy action (#23)

Author: Dimagaa

.github/workflows/deploy-to-ecr.yml

@@ -1,7 +1,8 @@
 name: Deploy to ECR
 
-on: workflow_dispatch
-
+on:
+  push:
+    branches: [ main ]
 env:
   AWS_REGION: us-east-1
   AWS_ASSUME_ROLE: arn:aws:iam::410123344539:role/github-botblend-role