[pypi] Very old releases don't have data on the API

See https://pypi.org/pypi/numpy/json

.editorconfig

@@ -11,3 +11,6 @@ trim_trailing_whitespace = true
 indent_style = space
 indent_size = 2
 insert_final_newline = true
+
+[*.py]
+indent_size = 4

src/pypi.py

@@ -32,7 +32,7 @@ def fetch_releases(pypi_id, regex):
             for r in regex:
                 if re.match(r, version):
                     matches = True
-            if matches:
+            if matches and R:
                 d = datetime.fromisoformat(R[0]["upload_time"]).strftime("%Y-%m-%d")
                 releases[version] = d
                 print("%s: %s" % (version, d))