I can’t speak to why the key is lowercased now (I’m sure there was much thought put into the decision).
But, you can easily achieve what you want by organizing your params a bit differently – use an array of objects:
{
"references" : [
{
"title" : "Some Title",
"url" : "https://example.com"
},
{
"title" : "Some Title",
"url" : "https://example.com"
},
{
"title" : "Some Title",
"url" : "https://example.com"
}
]
}
Then in your template:
<ul>
{{ range .Params.references }}
<li><a href="{{ .url }}" target="_blank" rel="nofollow">{{ .title }}</a></li>
{{ end }}
</ul>