Fix HTTP header name

Author: emyller

src/common/core/middleware.py

@@ -18,7 +18,7 @@ def __init__(
 
     def __call__(self, request: HttpRequest) -> HttpResponse:
         response = self.get_response(request)
-        response.headers["X-Flagsmith-Version"] = self.get_version()
+        response.headers["Flagsmith-Version"] = self.get_version()
         return response
 
     def get_version(self) -> str:

tests/unit/common/core/test_middleware.py

@@ -28,7 +28,7 @@ def test_APIResponseVersionHeaderMiddleware__valid_version_info___adds_version_h
 
     # Then
     assert result == response
-    assert response.headers["X-Flagsmith-Version"] == "v1.2.3"
+    assert response.headers["Flagsmith-Version"] == "v1.2.3"
     assert get_response.call_args_list == [mocker.call(request)]
     assert get_versions_from_manifest.call_args_list == [mocker.call()]
 
@@ -56,6 +56,6 @@ def test_APIResponseVersionHeaderMiddleware__invalid_version_info___adds_unknown
 
     # Then
     assert result == response
-    assert response.headers["X-Flagsmith-Version"] == "unknown"
+    assert response.headers["Flagsmith-Version"] == "unknown"
     assert get_response.call_args_list == [mocker.call(request)]
     assert get_versions_from_manifest.call_args_list == [mocker.call()]