Require dart 3.4, prepare for release v1.12.0 (#162)

Doing a minor release since features were added
diff --git a/.github/workflows/test-package.yml b/.github/workflows/test-package.yml
index 25edb67..bbdb9d2 100644
--- a/.github/workflows/test-package.yml
+++ b/.github/workflows/test-package.yml
@@ -47,7 +47,7 @@
       matrix:
         # Add macos-latest and/or windows-latest if relevant for this package.
         os: [ubuntu-latest]
-        sdk: [3.1, dev]
+        sdk: [3.4, dev]
     steps:
       - uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332
       - uses: dart-lang/setup-dart@0a8a0fc875eb934c15d08629302413c671d3f672
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 029f155..56aa7f6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,7 +1,7 @@
-## 1.11.2-wip
+## 1.12.0
 
-* Require Dart 3.1 or greater
 * Added support for parsing Wasm frames of Chrome (V8), Firefox, Safari.
+* Require Dart 3.4 or greater
 
 ## 1.11.1
 
diff --git a/lib/src/stack_zone_specification.dart b/lib/src/stack_zone_specification.dart
index 7309ce0..901a5ee 100644
--- a/lib/src/stack_zone_specification.dart
+++ b/lib/src/stack_zone_specification.dart
@@ -158,7 +158,7 @@
     try {
       // TODO(rnystrom): Is the null-assertion correct here? It is nullable in
       // Zone. Should we check for that here?
-      self.parent!.runBinary(_onError!, error, stackChain);
+      self.parent!.runBinary(_onError, error, stackChain);
     } on Object catch (newError, newStackTrace) {
       if (identical(newError, error)) {
         parent.handleUncaughtError(zone, error, stackChain);
diff --git a/pubspec.yaml b/pubspec.yaml
index 2438909..a06cd6f 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,10 +1,10 @@
 name: stack_trace
-version: 1.11.2-wip
+version: 1.12.0
 description: A package for manipulating stack traces and printing them readably.
 repository: https://github.com/dart-lang/stack_trace
 
 environment:
-  sdk: ^3.1.0
+  sdk: ^3.4.0
 
 dependencies:
   path: ^1.8.0