misc: support v1 json_annotation

Verified that v1 changes don't affect runtime behavior

pkgs/pubspec_parse/CHANGELOG.md

diff --git a/pkgs/pubspec_parse/CHANGELOG.md b/pkgs/pubspec_parse/CHANGELOG.md
index 2447adb..d114b8c 100644
--- a/pkgs/pubspec_parse/CHANGELOG.md
+++ b/pkgs/pubspec_parse/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 0.1.2+2
+
+- Support `package:json_annotation` v1.
+
 ## 0.1.2+1
 
 - Support the Dart 2 stable release.

pkgs/pubspec_parse/pubspec.yaml

diff --git a/pkgs/pubspec_parse/pubspec.yaml b/pkgs/pubspec_parse/pubspec.yaml
index eaedffb..17ff7d3 100644
--- a/pkgs/pubspec_parse/pubspec.yaml
+++ b/pkgs/pubspec_parse/pubspec.yaml
@@ -2,7 +2,7 @@
 description: >-
   Simple package for parsing pubspec.yaml files with a type-safe API and rich
   error reporting.
-version: 0.1.2+1
+version: 0.1.2+2
 homepage: https://github.com/dart-lang/pubspec_parse
 author: Dart Team <misc@dartlang.org>
 
@@ -10,7 +10,7 @@
   sdk: '>=2.0.0-dev.54 <3.0.0'
 
 dependencies:
-  json_annotation: ^0.2.9
+  json_annotation: '>=0.2.9 <2.0.0'
   pub_semver: ^1.3.2
   yaml: ^2.1.12