Fix error in deployment steps

[desertaxle]

Switches to the sync version of DefaultAzureCredential to resolve errors when using default credentials with the deployment steps in this library.

Closes PrefectHQ/prefect#10764
Closes #115

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• References any related issue by including "Closes #" or "Closes ".
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• Includes tests or only affects documentation.
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• Summarizes PR's changes in CHANGELOG.md

[zzstoatzz]

lgtm!