allow the <=2.9.10 stable sdk and bump version (#34)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 549b1dd..b8fb9b0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 1.3.1-nullsafety.1
+
+* Allow the <=2.9.10 stable sdks.
+
 ## 1.3.0-nullsafety
 
 * Migrate to NNBD
diff --git a/pubspec.yaml b/pubspec.yaml
index dd4b772..4c7e761 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,15 +1,15 @@
 name: typed_data
-version: 1.3.0-nullsafety
+version: 1.3.0-nullsafety.1
 
 description: >-
   Utility functions and classes related to the dart:typed_data library.
 homepage: https://github.com/dart-lang/typed_data
 
 environment:
-  sdk: '>=2.9.0-18.0 <2.9.0'
+  sdk: '>=2.9.0-18.0 <=2.9.10'
 
 dependencies:
-  collection: '>=1.15.0-nnbd <1.15.0'
+  collection: '>=1.15.0-nullsafety <1.15.0'
 
 dev_dependencies:
   pedantic: ^1.9.0
@@ -17,87 +17,50 @@
 
 dependency_overrides:
   async:
-    git:
-      url: git://github.com/dart-lang/async.git
-      ref: null_safety
+    git: git://github.com/dart-lang/async.git
   boolean_selector:
-    git:
-      url: git://github.com/dart-lang/boolean_selector.git
-      ref: null_safety
+    git: git://github.com/dart-lang/boolean_selector.git
   charcode:
-    git:
-      url: git://github.com/dart-lang/charcode.git
-      ref: null_safety
-  collection:
-    git:
-      url: git://github.com/dart-lang/collection.git
-      ref: null_safety
+    git: git://github.com/dart-lang/charcode.git
   js:
     git:
       url: git://github.com/dart-lang/sdk.git
-      ref: null_safety-pkgs
       path: pkg/js
   matcher:
-    git:
-      url: git://github.com/dart-lang/matcher.git
-      ref: null_safety
+    git: git://github.com/dart-lang/matcher.git
   meta:
     git:
       url: git://github.com/dart-lang/sdk.git
-      ref: null_safety-pkgs
       path: pkg/meta
   path:
-    git:
-      url: git://github.com/dart-lang/path.git
-      ref: null_safety
+    git: git://github.com/dart-lang/path.git
   pedantic:
-    git:
-      url: git://github.com/dart-lang/pedantic.git
-      ref: null_safety
+    git: git://github.com/dart-lang/pedantic.git
   pool:
-    git:
-      url: git://github.com/dart-lang/pool.git
-      ref: null_safety
+    git: git://github.com/dart-lang/pool.git
   source_maps:
-    git:
-      url: git://github.com/dart-lang/source_maps.git
-      ref: null_safety
+    git: git://github.com/dart-lang/source_maps.git
   source_map_stack_trace:
-    git:
-      url: git://github.com/dart-lang/source_map_stack_trace.git
-      ref: null_safety
+    git: git://github.com/dart-lang/source_map_stack_trace.git
   source_span:
-    git:
-      url: git://github.com/dart-lang/source_span.git
-      ref: null_safety
+    git: git://github.com/dart-lang/source_span.git
   stack_trace:
-    git:
-      url: git://github.com/dart-lang/stack_trace.git
-      ref: null_safety
+    git: git://github.com/dart-lang/stack_trace.git
   stream_channel:
-    git:
-      url: git://github.com/dart-lang/stream_channel.git
-      ref: null_safety
+    git: git://github.com/dart-lang/stream_channel.git
   string_scanner:
-    git:
-      url: git://github.com/dart-lang/string_scanner.git
-      ref: null_safety
+    git: git://github.com/dart-lang/string_scanner.git
   term_glyph:
-    git:
-      url: git://github.com/dart-lang/term_glyph.git
-      ref: null_safety
+    git: git://github.com/dart-lang/term_glyph.git
   test_api:
     git:
       url: git://github.com/dart-lang/test.git
-      ref: null_safety
       path: pkgs/test_api
   test_core:
     git:
       url: git://github.com/dart-lang/test.git
-      ref: null_safety
       path: pkgs/test_core
   test:
     git:
       url: git://github.com/dart-lang/test.git
-      ref: null_safety
       path: pkgs/test