Replaced the requirements.txt in the docs directory with the Read the Docs configuration file.

.readthedocs.yaml

@@ -0,0 +1,40 @@
+# The Flask HTTP Digest Authentication Project.
+# Author: imacat@mail.imacat.idv.tw (imacat), 2023/4/5
+
+#  Copyright (c) 2023 imacat.
+#
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+
+# .readthedocs.yaml
+# Read the Docs configuration file
+# See https://docs.readthedocs.io/en/stable/config-file/v2.html for details
+
+# Required
+version: 2
+
+# Set the version of Python and other tools you might need
+build:
+  os: ubuntu-22.04
+  tools:
+    python: "3.7"
+
+# Build documentation in the docs/ directory with Sphinx
+
+# If using Sphinx, optionally build your docs in additional formats such as PDF
+formats: all
+
+# Optionally declare the Python requirements required to build your docs
+python:
+   install:
+   - method: pip
+     path: .

docs/requirements.txt

@@ -1 +0,0 @@
-flask