Changed Azure region (#66)

Issue #65
Changed the Azure region because US-Central has a quota of 0 instances for free accounts.

Author: olegmlsn

.github/steps/3-spinup-environment.md

@@ -47,7 +47,7 @@ env:
   IMAGE_REGISTRY_URL: ghcr.io
   AZURE_RESOURCE_GROUP: cd-with-actions
   AZURE_APP_PLAN: actions-ttt-deployment
-  AZURE_LOCATION: '"Central US"'
+  AZURE_LOCATION: '"East US"'
   ###############################################
   ### Replace <username> with GitHub username ###
   ###############################################