raise the minimum supported version

Bitvec works from Rust 1.44.0

.travis.yml

@@ -8,7 +8,7 @@ rust:
   - nightly
   - beta
   - stable
-  - 1.37.0
+  - 1.44.0
 
 env:
   matrix:
@@ -25,8 +25,8 @@ matrix:
     - rust: stable
       env: FEATURES='--no-default-features'
       # still compatible with 1.36.0 if not using lexical-core
-    - rust: 1.36.0
-      env: FEATURES='--no-default-features --features std'
+    - rust: 1.37.0
+      env: FEATURES='--no-default-features --features "regexp lexical"'
     - rust: stable
       env: FEATURES='--no-default-features --features "alloc"'
     - rust: nightly

README.md

@@ -5,7 +5,7 @@
 [![Build Status](https://travis-ci.org/Geal/nom.svg?branch=master)](https://travis-ci.org/Geal/nom)
 [![Coverage Status](https://coveralls.io/repos/Geal/nom/badge.svg?branch=master)](https://coveralls.io/r/Geal/nom?branch=master)
 [![Crates.io Version](https://img.shields.io/crates/v/nom.svg)](https://crates.io/crates/nom)
-[![Minimum rustc version](https://img.shields.io/badge/rustc-1.36.0+-lightgray.svg)](#rust-version-requirements)
+[![Minimum rustc version](https://img.shields.io/badge/rustc-1.44.0+-lightgray.svg)](#rust-version-requirements)
 
 nom is a parser combinators library written in Rust. Its goal is to provide tools
 to build safe parsers without compromising the speed or memory consumption. To
@@ -188,7 +188,7 @@ Some benchmarks are available on [Github](https://github.com/Geal/nom_benchmarks
 
 ## Rust version requirements
 
-The 5.0 series of nom requires **Rustc version 1.37 or greater** (compatible with 1.36 if building without the `lexical` feature which includes the `lexical-core` dependency).
+The 6.0 series of nom requires **Rustc version 1.44 or greater** (compatible with 1.37 if building without the `alloc` or `std` features, ie `--no-default-features --features="regex,lexical"`).
 
 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.

build.rs

@@ -1,7 +1,7 @@
 extern crate version_check;
 
 fn main() {
-  if version_check::is_min_version("1.28.0").unwrap_or(true) {
+  if version_check::is_min_version("1.44.0").unwrap_or(true) {
     println!("cargo:rustc-cfg=stable_i128");
   }
 }