Bump crossbeam to 0.7.4

This just bumps the `rand` `dev-dependency` to `0.7`.
None of the underlying crates had breaking changes, and this crate has
no changes, so a patch release is fine.

Author: jonhoo

CHANGELOG.md

@@ -1,3 +1,7 @@
+# Version 0.7.4
+
+- Bump `rand` dev-dependency to version 0.7.
+
 # Version 0.7.3
 
 - Fix breakage with nightly feature due to rust-lang/rust#65214.

Cargo.toml

@@ -4,7 +4,7 @@ name = "crossbeam"
 # - Update CHANGELOG.md
 # - Update README.md
 # - Create "crossbeam-X.Y.Z" git tag
-version = "0.7.3"
+version = "0.7.4"
 authors = ["The Crossbeam Project Developers"]
 license = "MIT/Apache-2.0"
 readme = "README.md"
@@ -60,7 +60,7 @@ path = "./crossbeam-utils"
 default-features = false
 
 [dev-dependencies]
-rand = "0.6"
+rand = "0.7"
 
 [workspace]
 members = [