update ami id in cloudformation

Update-MDEC2ImageAMIID.ps1

# Get latest Amazon Windows Core AMI and update the ami id in the specified file.
# Needs the AWSPowerShell module installed and credentials configured.
Import-Module -Name AWSPowerShell

$windowsName = 'WINDOWS_2016_Core'
$region = 'eu-west-2'
$cfFileLocation = 'c:\cloudfromation\win-servers\ec2.yml'

#Get the latest AMI ID
$imageId = (Get-EC2ImageByName -Name $windowsName -Region $region).ImageId

# Get the existing AMI ID from the cloudformation yaml file
$existingImageid = (Select-String -Path $cfFileLocation -Pattern "ami-[0-9a-f]{8}" -CaseSensitive).Matches.Value

# Update the AMI ID
(Get-Content -Path $cfFileLocation).Replace($existingImageid, $imageId) | Set-Content -Path $cfFileLocation -Force