ci: sync with ndn-cxx

Change-Id: I2febf1fd7e8000d077383fd495b8b1b82e284477
diff --git a/docs/requirements.txt b/docs/requirements.txt
new file mode 100644
index 0000000..1348feb
--- /dev/null
+++ b/docs/requirements.txt
@@ -0,0 +1,3 @@
+docutils>=0.20
+sphinx>=7.0.1,<9
+sphinxcontrib-doxylink~=1.13