chore: Rust 1.89 promoted file locking to the standard library, so prefer stdlib to fs2 (#2467)

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* __->__ #2467
* #2465

codex-rs/Cargo.lock

@@ -703,7 +703,6 @@ dependencies = [
  "dirs",
  "env-flags",
  "eventsource-stream",
- "fs2",
  "futures",
  "landlock",
  "libc",
@@ -1745,16 +1744,6 @@ dependencies = [
  "percent-encoding",
 ]
 
-[[package]]
-name = "fs2"
-version = "0.4.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9564fc758e15025b46aa6643b1b77d047d1a56a1aea6e01002ac0c7026876213"
-dependencies = [
- "libc",
- "winapi",
-]
-
 [[package]]
 name = "futures"
 version = "0.3.31"