Bump min Dart SDK to 2.7 (dart-lang/test_descriptor#24)

pkgs/test_descriptor/.travis.yml

diff --git a/pkgs/test_descriptor/.travis.yml b/pkgs/test_descriptor/.travis.yml
index 3fa092b..8914450 100644
--- a/pkgs/test_descriptor/.travis.yml
+++ b/pkgs/test_descriptor/.travis.yml
@@ -2,7 +2,7 @@
 
 dart:
   - dev
-  - 2.1.0
+  - 2.7.0
 
 dart_task:
   - test
@@ -14,7 +14,7 @@
   - dart: dev
     dart_task:
       dartanalyzer: --fatal-infos --fatal-warnings .
-  - dart: 2.1.0
+  - dart: 2.7.0
     dart_task:
       dartanalyzer: --fatal-warnings .
 

pkgs/test_descriptor/CHANGELOG.md

diff --git a/pkgs/test_descriptor/CHANGELOG.md b/pkgs/test_descriptor/CHANGELOG.md
index 8fbc4b7..6d4156d 100644
--- a/pkgs/test_descriptor/CHANGELOG.md
+++ b/pkgs/test_descriptor/CHANGELOG.md
@@ -1,5 +1,6 @@
-## 1.2.1
+## 1.2.1-dev
 
+* Update minimum Dart SDK to `2.7.0`.
 * Fix outdated URLs in `README.md`.
 
 ## 1.2.0

pkgs/test_descriptor/pubspec.yaml

diff --git a/pkgs/test_descriptor/pubspec.yaml b/pkgs/test_descriptor/pubspec.yaml
index c21b71b..08a3192 100644
--- a/pkgs/test_descriptor/pubspec.yaml
+++ b/pkgs/test_descriptor/pubspec.yaml
@@ -4,7 +4,7 @@
 homepage: https://github.com/dart-lang/test_descriptor
 
 environment:
-  sdk: '>=2.1.0 <3.0.0'
+  sdk: '>=2.7.0 <3.0.0'
 
 dependencies:
   archive: '^2.0.0'