Update Python package dependencies in GovCloud deployment guide

Author: Bob Strahan

docs/govcloud-deployment.md

@@ -42,7 +42,7 @@ You need to have the following packages installed on your computer:
 3. [sam (AWS SAM)](https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/install-sam-cli.html)
 4. python 3.11 or later
 5. A local Docker daemon
-6. Python packages for publish.py: `pip install boto3 typer rich botocore setuptools`
+6. Python packages for publish.py: `pip install boto3 rich PyYAML botocore setuptools`
 
 ### Step 1: Generate GovCloud Template