Update main-build.yml (#1217)

Adding workflow_dispatch for manual run option.

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Author: Miqueasher

.github/workflows/main-build.yml

@@ -4,6 +4,7 @@ on:
     branches:
       - main
       - "release/v*"
+  workflow_dispatch: # be able to run the workflow on demand
 env:
   AWS_DEFAULT_REGION: us-east-1
   STAGING_ECR_REGISTRY: 611364707713.dkr.ecr.us-west-2.amazonaws.com