SSL4EO: fix sampling script (#1510)

experiments/ssl4eo/sample_ssl4eo.py

@@ -53,7 +53,7 @@ def get_world_cities(
     cols = ["city", "lat", "lng", "population"]
     cities = pd.read_csv(os.path.join(download_root, filename), usecols=cols)
     cities.at[8436, "population"] = 50789  # fix one bug (Tecax) in the csv file
-    cities = cities.nlargest("population", size)
+    cities = cities.nlargest(size, "population")
     return cities