fix CI (#20)

Fix the following Github action error..

```
validation error detected: Value 'GitHubActions-Sage-Bionetworks-IT-packer-ami-template-11112909383'
at 'roleSessionName' failed to satisfy constraint: Member must have length less than or equal to 64
```

.github/workflows/deploy.yaml

@@ -49,7 +49,7 @@ jobs:
       with:
         aws-region: ${{ env.AWS_REGION }}
         role-to-assume: ${{ env.AWS_ROLE_TO_ASSUME }}
-        role-session-name: GitHubActions-${{ github.repository_owner }}-${{ github.event.repository.name }}-${{ github.run_id }}
+        role-session-name: GA-${{ github.repository_owner }}-${{ github.event.repository.name }}-${{ github.run_id }}
         role-duration-seconds: 3600
     - name: Build and Upload AMI
       run: |