fix: use local dataset for CLV tests (#1412)

- Modified test_utils.py to use local CLV dataset instead of downloading from GitHub.
- Ensured the dataset is included in the repository.

tests/clv/test_utils.py

@@ -86,8 +86,7 @@ def fitted_gg(test_summary_data) -> GammaGammaModel:
 # TODO: Consolidate this fixture into the tests requiring it?
 @pytest.fixture()
 def df_cum_transactions():
-    url_cdnow = "https://raw.githubusercontent.com/pymc-labs/pymc-marketing/main/data/cdnow_transactions.csv"
-    cdnow_transactions = pd.read_csv(url_cdnow)
+    cdnow_transactions = pd.read_csv("data/cdnow_transactions.csv")
 
     rfm_data = rfm_summary(
         cdnow_transactions,