Update rand dependency for test-float-parse

This removes a dependency on fuchsia-cprng which doesn't have any
license info.

Author: bjorn3

src/etc/test-float-parse/Cargo.toml

@@ -8,7 +8,7 @@ publish = false
 resolver = "1"
 
 [dependencies]
-rand = "0.4"
+rand = "0.8"
 
 [lib]
 name = "test_float_parse"