doc: Pin pip to <25.3 for RTD as a workaround for pybind

Readthedocs now uses pip 25.3 by default which requires PEP 517.
src/pybind/* does not provide pyproject.toml files for PEP 517.
For an immediate workaround to allow RTD builds to succeed, pin pip
version to earlier than 25.3.

Details for pybind in https://tracker.ceph.com/issues/73645

Signed-off-by: Ville Ojamo <14869000+bluikko@users.noreply.github.com>
(cherry picked from commit a65c46c24952a4f5778c0b68b0e7cf26df32757a)

diff --git a/admin/doc-read-the-docs.txt b/admin/doc-read-the-docs.txt
index 7e0ecc86d75b004be2dcb37f5f9bca6dd1023893..6e68ada473b82b5aca0a22a4b87114193da4afd3 100644 (file)
--- a/admin/doc-read-the-docs.txt
+++ b/admin/doc-read-the-docs.txt
@@ -1,2 +1,3 @@
 plantweb
 git+https://github.com/readthedocs/readthedocs-sphinx-search@main
+pip < 25.3