Support package:build 0.8.x (#141)

There are no breaking changes as far as source_gen is concerned

- Bump versions of build_test and build_runner
- Stop testing on SDKs older than 1.21 since they are not compatible with build 0.8.0

Author: natebosch

.travis.yml

@@ -5,8 +5,6 @@ dart:
   - stable
   - 1.22.1
   - 1.21.1
-  - 1.20.1
-  - 1.19.1
 cache:
   directories:
     - $HOME/.pub-cache

CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.5.4+4
+
+* Support package:build 0.8.x
+
 ## 0.5.4+3
 
 * Support the latest release of `pkg/dart_style`.

pubspec.yaml

@@ -1,18 +1,18 @@
 name: source_gen
-version: 0.5.4+3
+version: 0.5.4+4
 author: Dart Team <[email protected]>
 description: Automatic sourcecode generation for Dart
 homepage: https://github.com/dart-lang/source_gen
 environment:
   sdk: '>=1.12.0 <2.0.0'
 dependencies:
   analyzer: ^0.29.2
-  build: ^0.7.1
+  build: '>=0.7.1 <0.9.0'
   dart_style: '>=0.1.7 <2.0.0'
   path: ^1.3.2
 dev_dependencies:
-  build_runner: ^0.3.0
-  build_test: ^0.4.0
+  build_runner: ^0.3.1+1
+  build_test: ^0.5.1
   cli_util: ^0.0.1
   collection: ^1.1.2
   mockito: '>=0.11.0 <3.0.0'