vm creation fails as almalinux offer and plan no longer exist

[jessereynolds]

Describe the Bug

Creation of the environment fails with the following error:

│ Error: creating Linux Virtual Machine "pe-server-0-4f3acb" (Resource Group "azure-pe_arch-test"): compute.VirtualMachinesClient#CreateOrUpdate: Failure sending request: StatusCode=0 -- Original Error: Code="ResourcePurchaseValidationFailed" Message="User failed validation to purchase resources. Error message: 'Offer with PublisherId: 'almalinux', OfferId: 'almalinux' cannot be purchased due to validation errors. For more information see details. Correlation Id: 'a77bf1c9-e69f-3db0-e682-a37048c96389' Offer with PublisherId: 'almalinux', OfferId: 'almalinux' and PlanId: 8-gen2 was removed from the marketplace for new purchase. See similar offers here 'https://azuremarketplace.microsoft.com/en-us/marketplace/apps?page=1%26search=almalinux%20almalinux'. Correlation Id 'a77bf1c9-e69f-3db0-e682-a37048c96389'.'"
│
│   with module.instances.azurerm_linux_virtual_machine.server[0],
│   on modules/instances/main.tf line 45, in resource "azurerm_linux_virtual_machine" "server":
│   45: resource "azurerm_linux_virtual_machine" "server" {

Alma Linux have added the architecture to the offer name, so instance_image should now be almalinux:almalinux-x86_64:8-gen2:latest and plan should be left empty. PR incoming.

Expected Behavior

Creation of the environment succeeds

Steps to Reproduce

Use the steps in the readme to create a simple environment (or any environment)

Additional Context

[jessereynolds]

Fixed in #20