fix(docs): add a build.tools.python entry

Specifying build.tools is mandatory. We use python, so use the latest
one available. For ubuntu 22.04 that should be 3.10 or thereabouts.

Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
Change-Id: Ifd184b9f3b2d8e91182ccb73c47b148e4aeaff05
diff --git a/.readthedocs.yaml b/.readthedocs.yaml
index af3fba0..de171ae 100644
--- a/.readthedocs.yaml
+++ b/.readthedocs.yaml
@@ -11,6 +11,8 @@
 
 build:
   os: ubuntu-22.04 # Ubuntu Jammy LTS
+  tools:
+    python: 3
 
 python:
   install: