How do I create a new repo via 2.0 API and powershell?

[ithryeandeus]

I've read the documentation, and I've formatted my request body just like in the example with 1 addition: 

$headers = New-Object "System.Collections.Generic.Dictionary[[String],[String]]"
$headers.Add('Authorization' , "$apiKey")
$headers.Add('accept', 'application/json')
$body=@"
{
"scm": "git",
"project": {
"key": "$MYKEY",
},
"is_private":$true
}
"@

try {
[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12
Invoke-RestMethod -Method PUT -Headers $headers -Body $body -Uri https://api.bitbucket.org/2.0/repositories/$workspace/$repoName -Verbose -UseBasicParsing
} catch {
echo "Something occured"
echo $_.Exception
echo $_
}

No matter what I put in the body, regardless of whether or not it's valid JSON, I always get a 200 response, the project KEY is wrong (defaults to oldest project in account), and it's not marked as a private repo. 

How am I supposed to format this request so that it works in powershell?