Fix release note template.

Fix release note template to use the variables we define, instead of a
bunch of variables that aren't available.

Author: Paddy Carver

cmd/changelog-build/release-note.tmpl

@@ -1,3 +1,3 @@
 {{- define "note" -}}
-{{if eq "new-resource" .Type}}**New Resource:** {{else if eq "new-datasource" .Type}}**New Data Source:** {{ end }}{{.Text }} ([#{{- .PRNumber -}}]({{- .PRURL -}}))
+{{if eq "new-resource" .Type}}**New Resource:** {{else if eq "new-datasource" .Type}}**New Data Source:** {{ end }}{{.Body}} ([GH-{{- .Issue -}}])
 {{- end -}}