Move crossbeam-epoch 0.9.18 -> 0.9.21 (RUSTSEC-2026-0204, invalid pointer
dereference in fmt::Pointer for Atomic/Shared) with `cargo update -p
crossbeam-epoch@0.9.18`; semver-compatible. Also records the crate's own
version, which upstream's 1.0.10 lockfile left at 1.0.9.

--- a/Cargo.lock
+++ b/Cargo.lock
@@ -10,7 +10,7 @@
 
 [[package]]
 name = "blake3"
-version = "1.0.9"
+version = "1.0.10"
 dependencies = [
  "blake3 1.8.7",
  "hex",
@@ -76,9 +76,9 @@
 
 [[package]]
 name = "crossbeam-epoch"
-version = "0.9.18"
+version = "0.9.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5b82ac4a3c2ca9c3460964f020e1402edd5753411d7737aa39c3714ad1b5420e"
+checksum = "dc74980687109a3b14c72fd458107bf0baa1da1a1a805e178d15501ba9b86d9d"
 dependencies = [
  "crossbeam-utils",
 ]