Clean up dependency output

Show new tag when dependencies don't have a previous version.
Align dependencies into columns.
Sort dependencies by name.

Signed-off-by: Derek McGowan <derek@mcgstyle.net>

cmd/containerd-release/template.go

@@ -48,7 +48,7 @@ https://github.com/{{.GithubRepo}}/issues.
 
 Previous release can be found at [{{.Previous}}](https://github.com/{{.GithubRepo}}/releases/tag/{{.Previous}})
 {{range $dep := .Dependencies}}
-* {{$dep.Previous}} -> {{$dep.Commit}} **{{$dep.Name}}**
+* **{{$dep.Name}}**	{{if $dep.Previous}}{{$dep.Previous}} -> {{$dep.Commit}}{{else}}{{$dep.Commit}} **_new_**{{end}}
 {{- end}}
 `
 )