Fix an edge case in dependency freshness checking.

lib/src/entrypoint.dart

Index: lib/src/entrypoint.dart
diff --git a/lib/src/entrypoint.dart b/lib/src/entrypoint.dart
index e0c6774a9c227945f26faff7fd8d843a585b76a8..0152926be06f375f9d77133da49fd124981d524f 100644
--- a/lib/src/entrypoint.dart
+++ b/lib/src/entrypoint.dart
@@ -536,6 +536,8 @@ class Entrypoint {
 
   /// Returns whether the locked version of [dep] matches the dependency.
   bool _isDependencyUpToDate(PackageDep dep) {
+    if (dep.name == root.name) return true;
+
     var locked = lockFile.packages[dep.name];
     if (locked == null) return false;