Deprecate const parameter of Field

tests/test_pydantic/test_field.py

@@ -54,3 +54,13 @@ def test_repr():
 
     instance = Model(id=123, foo="bar")
     assert "foo=" not in repr(instance)
+
+
+def test_const_is_deprecated():
+    with pytest.warns(
+        DeprecationWarning,
+        match="`const` is deprecated and doesn't work, use `Literal` instead",
+    ):
+
+        class Model(SQLModel):
+            int_value: int = Field(default=10, const=True)