prep for merge to master (#12)

.travis.yml

diff --git a/.travis.yml b/.travis.yml
index ecdac91..0ff7989 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,11 +1,10 @@
 language: dart
 
 dart:
-  - 2.0.0
   - dev
 
 dart_task:
-  - dart_analyzer: --fatal-warnings --fatal-infos .
+  - dart_analyzer: --enable-experiment=non-nullable --fatal-warnings --fatal-infos .
 
 matrix:
   include:
@@ -15,7 +14,7 @@
 
 # Only building master means that we don't run two builds for each pull request.
 branches:
-  only: [master]
+  only: [master, null_safety]
 
 cache:
  directories:

CHANGELOG.md

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 16a9f22..7f3fc36 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 1.2.0-nullsafety
+
+- Opt in to null safety.
+
 ## 1.1.3
 
 - Added example, fixed recommended lints.

pubspec.yaml

diff --git a/pubspec.yaml b/pubspec.yaml
index 52ae724..be87ff8 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,12 +1,12 @@
 name: charcode
-version: 1.1.3
+version: 1.2.0-nullsafety
 description: >-
   Constants for ASCII and common non-ASCII character codes represented by
   top-level constants.
 homepage: https://github.com/dart-lang/charcode
 
 environment:
-  sdk: '>=2.9.0-0 <3.0.0'
+  sdk: '>=2.9.0-18.0 <2.9.0'
 
 dev_dependencies:
   pedantic: ^1.0.0