remove the bitvec input type

bitvec integration has caused some dependency issues, that were solved,
but still raises the minimum rust version significantly, which will be
problematic for some distributions like Debian.

The input traits implementations for bitvec types have been moved to the
nom-bitvec crate, so we can keep the functionality without affecting
basic nom usage

Cargo.toml

@@ -30,19 +30,11 @@ include = [
 [features]
 alloc = []
 std = ["alloc", "memchr/use_std"]
-bitvec-base = ["bitvec"]
-bitvec-alloc = ["alloc", "bitvec/alloc"]
-bitvec-std = ["bitvec/std", "std"]
 default = ["std", "lexical"]
 regexp = ["regex"]
 lexical = ["lexical-core"]
 docsrs = []
 
-[dependencies.bitvec]
-version = ">= 0.22.3"
-optional = true
-default-features = false
-
 [dependencies.regex]
 version = "^1.0"
 optional = true

README.md

@@ -190,7 +190,6 @@ Some benchmarks are available on [Github](https://github.com/Geal/nom_benchmarks
 
 The 6.0 series of nom requires **Rustc version 1.44 or greater**, but it can change for some feature combinations:
 - compatible with 1.41.1 if building without the `alloc` or `std` features, ie `--no-default-features --features="regex,lexical"`
-- compatible with 1.51 if using the bitvec features
 
 Travis CI always has a build with a pinned version of Rustc matching the oldest supported Rust release.
 The current policy is that this will only be updated in the next major nom release.

src/lib.rs

@@ -411,8 +411,6 @@
 #[cfg(feature = "alloc")]
 #[macro_use]
 extern crate alloc;
-#[cfg(feature = "bitvec")]
-pub extern crate bitvec;
 #[cfg(doctest)]
 extern crate doc_comment;
 #[cfg(feature = "lexical")]