[helpers] Fix get() call in download_file() (#3825)

get() is a function and not an object with __enter__ (aka context manager)

src/poetry/utils/helpers.py

@@ -98,7 +98,7 @@ def download_file(
 
 
     get = requests.get if not session else session.get
     get = requests.get if not session else session.get
 
 
-    with get(url, stream=True) as response:
+    response = get(url, stream=True)
     response.raise_for_status()
     response.raise_for_status()
 
 
     with open(dest, "wb") as f:
     with open(dest, "wb") as f: