Bumps nimble v0.16.4 (#24437)

(cherry picked from commit be4d19e562)

tools/deps.nim

@@ -42,3 +42,9 @@ proc cloneDependency*(destDirBase: string, url: string, commit = commitHead,
     discard "this dependency was bundled with Nim, don't do anything"
   else:
     quit "FAILURE: " & destdir & " already exists but is not a git repo"
+
+proc updateSubmodules*(dir: string) =
+  let oldDir = getCurrentDir()
+  setCurrentDir(dir)
+  exec "git submodule update --init"
+  setCurrentDir(oldDir)