Prepare for 1.3.0 release (#379)

CHANGELOG.md

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 50b9d27..0aff1ef 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,4 +1,5 @@
-## 1.3.0-dev
+## 1.3.0 - 2022-5-11
+
 * Bump the minimum Dart SDK version to 2.15.0
 * Add a `--package` flag, which takes the package's root directory, instead of
   the .package file. Deprecate the `--packages` flag.
@@ -10,7 +11,7 @@
 * Use the `libraryFilters` option in `getSourceReport` to speed up coverage runs
   that use `scopedOutput`.
 
-## 1.2.0
+## 1.2.0 - 2022-3-24
 
 * Support branch level coverage information, when running tests in the Dart VM.
   This is not supported for web tests yet.

pubspec.yaml

diff --git a/pubspec.yaml b/pubspec.yaml
index f9f8078..75539cf 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,5 +1,5 @@
 name: coverage
-version: 1.3.0-dev
+version: 1.3.0
 description: Coverage data manipulation and formatting
 repository: https://github.com/dart-lang/coverage