Fix UB from miri in drop - update to latest crossbeam to resolve

Author: Firstyear

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "concread"
-version = "0.1.7"
+version = "0.1.8"
 authors = ["William Brown <william@blackhats.net.au>"]
 
 description = "Concurrently Readable Data-Structures for Rust"
@@ -11,16 +11,15 @@ readme = "README.md"
 keywords = ["data-structures", "concread", "concurrency", "parallel",]
 categories = ["data-structures", "memory-management",]
 license = "MPL-2.0"
-license-file = "LICENSE.md"
 
 [dependencies]
-crossbeam-epoch = "0.5"
-crossbeam-utils = "0.5"
-parking_lot = "0.6"
+crossbeam-epoch = "0.8"
+crossbeam-utils = "0.7"
+parking_lot = "0.10"
 num = "0.2.0"
 
 [dev-dependencies]
-time = "0.1"
+time = "0.2"
 rand = "0.7"
 
 [[bin]]