downloads: update CPython to 3.7.4

It was released yesterday.

Author: indygreg

pythonbuild/downloads.py

@@ -65,10 +65,10 @@
         'version': '3.13.2',
     },
     'cpython-3.7': {
-        'url': 'https://www.python.org/ftp/python/3.7.3/Python-3.7.3.tar.xz',
-        'size': 17108364,
-        'sha256': 'da60b54064d4cfcd9c26576f6df2690e62085123826cff2e667e72a91952d318',
-        'version': '3.7.3',
+        'url': 'https://www.python.org/ftp/python/3.7.4/Python-3.7.4.tar.xz',
+        'size': 17131432,
+        'sha256': 'fb799134b868199930b75f26678f18932214042639cd52b16da7fd134cd9b13f',
+        'version': '3.7.4',
         'licenses': ['Python-2.0', 'CNRI-Python'],
         'license_file': 'LICENSE.cpython.txt',
     },