Bump language version for pkg/native_stack_traces

Extracted from https://dart-review.googlesource.com/c/sdk/+/397164
Which migrates the sdk to resolve as a pub workspace

Pub workspaces requires a language version of 3.5.

Change-Id: I44dc73114c9c794cb60ab29b19aa4b1b00f3241d
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/412661
Reviewed-by: Daco Harkes <dacoharkes@google.com>
Commit-Queue: Sigurd Meldgaard <sigurdm@google.com>

pkg/native_stack_traces/CHANGELOG.md

@@ -1,3 +1,6 @@
+## 0.6.1-wip
+- Update SDK constraint to `^3.5.0`.
+
 ## 0.6.0
 - Make return type of DwarfContainer reader methods nullable so null
   can be returned if there is no relevant DWARF information.

pkg/native_stack_traces/lib/src/convert.dart

@@ -562,12 +562,12 @@ class DwarfStackTraceDecoder extends StreamTransformerBase<String, String> {
         Dwarf? unitDwarf;
         // Prefer the map that specifies loading unit IDs over the iterable.
         if (_dwarfByUnitId != null) {
-          unitDwarf = _dwarfByUnitId![unitId];
+          unitDwarf = _dwarfByUnitId[unitId];
         }
         if (unitDwarf == null &&
             _unitDwarfs != null &&
             offset.buildId != null) {
-          for (final d in _unitDwarfs!) {
+          for (final d in _unitDwarfs) {
             if (d.buildId(offset.architecture) == offset.buildId) {
               unitDwarf = d;
             }

pkg/native_stack_traces/pubspec.yaml

@@ -1,10 +1,10 @@
 name: native_stack_traces
-version: 0.6.0
+version: 0.6.1-wip
 description: Utilities for working with non-symbolic stack traces.
 repository: https://github.com/dart-lang/sdk/tree/main/pkg/native_stack_traces
 
 environment:
-  sdk: '>=3.0.0 <4.0.0'
+  sdk: ^3.5.0
 
 executables:
   decode: