🐛 Fix RuntimeError: dictionary changed size during iteration in sqlmodel_update() (#997)

Co-authored-by: Motov Yurii <109919500+YuriiMotov@users.noreply.github.com>

tests/test_update.py

@@ -0,0 +1,20 @@
+from sqlmodel import Field, SQLModel
+
+
+def test_sqlmodel_update():
+    class Organization(SQLModel, table=True):
+        id: int = Field(default=None, primary_key=True)
+        name: str
+        headquarters: str
+
+    class OrganizationUpdate(SQLModel):
+        name: str
+
+    org = Organization(name="Example Org", city="New York", headquarters="NYC HQ")
+    org_in = OrganizationUpdate(name="Updated org")
+    org.sqlmodel_update(
+        org_in,
+        update={
+            "headquarters": "-",  # This field is in Organization, but not in OrganizationUpdate
+        },
+    )