update constant_time_eq to v0.3.0

This bumps the MSRV of both `blake3` and `b3sum` to 1.66.1.

.github/workflows/ci.yml

@@ -34,7 +34,7 @@ jobs:
           # https://github.com/rust-lang/libs-team/issues/72.
           # This test target is here so that we notice if we accidentally bump
           # the MSRV, but it's not a promise that we won't bump it.
-          "1.60.0",
+          "1.66.1",
         ]
 
     steps:
@@ -145,10 +145,10 @@ jobs:
           "stable",
           "beta",
           "nightly",
-          # The b3sum MSRV is typically higher than the blake3 crate's, because
+          # The b3sum MSRV is sometimes higher than the blake3 crate's, because
           # b3sum depends on Clap. We check in the b3sum Cargo.lock, so Clap
           # update shouldn't randomly break us here.
-          "1.64.0",
+          "1.66.1",
         ]
 
     steps:

Cargo.toml

@@ -84,7 +84,7 @@ features = ["rayon"]
 [dependencies]
 arrayref = "0.3.5"
 arrayvec = { version = "0.7.0", default-features = false }
-constant_time_eq = "0.2.4"
+constant_time_eq = "0.3.0"
 rayon = { version = "1.2.1", optional = true }
 cfg-if = "1.0.0"
 digest = { version = "0.10.1", features = [ "mac" ], optional = true }