allow the 2.12 prerelease sdks (dart-lang/stack_trace#87)

pkgs/stack_trace/CHANGELOG.md

diff --git a/pkgs/stack_trace/CHANGELOG.md b/pkgs/stack_trace/CHANGELOG.md
index ef00a48..1e19614 100644
--- a/pkgs/stack_trace/CHANGELOG.md
+++ b/pkgs/stack_trace/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 1.10.0-nullsafety.5
+
+* Allow prerelease versions of the 2.12 sdk.
+
 ## 1.10.0-nullsafety.4
 
 * Allow the `2.10.0` stable and dev SDKs.

pkgs/stack_trace/pubspec.yaml

diff --git a/pkgs/stack_trace/pubspec.yaml b/pkgs/stack_trace/pubspec.yaml
index 4ffb4a0..7dbf9a8 100644
--- a/pkgs/stack_trace/pubspec.yaml
+++ b/pkgs/stack_trace/pubspec.yaml
@@ -1,11 +1,11 @@
 name: stack_trace
-version: 1.10.0-nullsafety.4
+version: 1.10.0-nullsafety.5
 description: A package for manipulating stack traces and printing them readably.
 homepage: https://github.com/dart-lang/stack_trace
 
 environment:
   # This must remain a tight constraint until nnbd is stable
-  sdk: '>=2.10.0-0.0.dev <2.11.0'
+  sdk: '>=2.10.0-0.0.dev <2.12.0'
 
 dependencies:
   path: ^1.8.0-nullsafety