update for the 2.10 dev sdk (#67)

This is in preparation for the actual 2.10 dev sdk release.
diff --git a/CHANGELOG.md b/CHANGELOG.md
index bafa706..8d2782c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,4 +1,4 @@
-## 1.10.0-nnbd
+## 1.10.0-nullsafety
 
 - Migrate to null safety.
 
diff --git a/pubspec.yaml b/pubspec.yaml
index 958487e..cb11f74 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,8 +1,9 @@
 name: pedantic
-version: 1.10.0-nnbd
+version: 1.10.0-nullsafety
 description: >-
   The Dart analyzer settings and best practices used internally at Google.
 homepage: https://github.com/dart-lang/pedantic
 
 environment:
-  sdk: '>=2.9.0-18.0 <2.9.0'
+  # This must remain a tight constraint until nnbd is stable
+  sdk: '>=2.10.0-0 <2.10.0'