Prepare a version of intl that supports the 2.12 sdk

PiperOrigin-RevId: 339283372
diff --git a/CHANGELOG.md b/CHANGELOG.md
index fb80a73..b3fcf38 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 0.17.0-nullsafety.1
+
+* Allow prereleases of the 2.12 Dart SDK.
+
 ## 0.17.0-nullsafety
 
  * Migrate to null safety.
diff --git a/pubspec.yaml b/pubspec.yaml
index 98c064f..ca12def 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,5 +1,5 @@
 name: intl
-version: 0.17.0-nullsafety
+version: 0.17.0-nullsafety.1
 homepage: https://github.com/dart-lang/intl
 description: >-
   Contains code to deal with internationalized/localized messages, date and
@@ -8,7 +8,7 @@
 
 environment:
   # This must remain a tight constraint until nnbd is stable
-  sdk: '>=2.11.0-180.0.dev <2.11.0'
+  sdk: '>=2.11.0-180.0.dev <2.12.0'
 
 dependencies:
   clock: ^1.1.0-nullsafety.1