update source_maps constraint (#1312)

diff --git a/pkgs/test_core/CHANGELOG.md b/pkgs/test_core/CHANGELOG.md
index c256afa..9ae715e 100644
--- a/pkgs/test_core/CHANGELOG.md
+++ b/pkgs/test_core/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 0.3.12-nullsafety.1
+
+* Update source_maps constraint.
+
 ## 0.3.12-nullsafety
 
 * Migrate to null safety.
diff --git a/pkgs/test_core/pubspec.yaml b/pkgs/test_core/pubspec.yaml
index 5158ee5..eca3e27 100644
--- a/pkgs/test_core/pubspec.yaml
+++ b/pkgs/test_core/pubspec.yaml
@@ -1,5 +1,5 @@
 name: test_core
-version: 0.3.12-nullsafety
+version: 0.3.12-nullsafety.1
 description: A basic library for writing tests and running them on the VM.
 homepage: https://github.com/dart-lang/test/blob/master/pkgs/test_core
 
@@ -22,7 +22,7 @@
   pedantic: '>=1.10.0-nullsafety <1.10.0'
   pool: '>=1.5.0-nullsafety <1.5.0'
   source_map_stack_trace: '>=2.1.0-nullsafety <2.1.0'
-  source_maps: '>=0.11.0-nullsafety <0.11.0'
+  source_maps: '>=0.10.10-nullsafety <0.10.10'
   source_span: '>=1.8.0-nullsafety <1.8.0'
   stack_trace: '>=1.10.0-nullsafety <1.10.0'
   stream_channel: ">=2.1.0-nullsafety <2.1.0"