Upgrade nom to v7 alpha to upgrade bitvec package transitively.

Author: bcmcmill

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "cexpr"
-version = "0.5.0"
+version = "0.6.0"
 edition = "2018"
 authors = ["Jethro Beekman <jethro@jbeekman.nl>"]
 license = "Apache-2.0/MIT"
@@ -13,7 +13,7 @@ keywords = ["C","expression","parser"]
 travis-ci = { repository = "jethrogb/rust-cexpr" }
 
 [dependencies]
-nom = { version = "6", default-features = false, features = ["std"] }
+nom = { version = "7.0.0-alpha2", default-features = false, features = ["std"] }
 
 [dev-dependencies]
-clang-sys = ">= 0.13.0, < 0.29.0"
+clang-sys = ">= 0.13.0, <= 1.2"