Changes to a lock file won't be written

[hasundue]

Under some situation, changes to a lock file won't be written by molt --write. For example:

cd test/fixtures
molt mod_test.ts --unstable-lock --write

which will output:

📦 @std/assert 0.222.0 => 0.226.0
  mod_test.ts
  deno.lock
📦 @std/testing 0.222.0 => 0.225.2
  deno.jsonc
  deno.lock
📦 deno.land/x/deno_graph 0.50.0 => 0.69.6
  mod.ts
  deno.lock

💾 deno.jsonc
💾 deno.lock
💾 mod_test.ts
💾 mod.ts

But the updates to @std/assert and @std/testing is not written to deno.lock.