Adjusted to use same Python and Ubuntu version for RDT

sliverc · sliverc · commit dce5f0b8e98a · 2023-02-21T10:32:57.000+04:00
In Github Actions to test the docs we use Python 3.8 and Ubuntu 22.04
so we should do the same on RDT.

This fixes current failing build (new Sphinx version needs Python 3.8)
diff --git a/.readthedocs.yaml b/.readthedocs.yaml
@@ -0,0 +1,6 @@
+version: 2
+
+build:
+  os: "ubuntu-22.04"
+  tools:
+    python: "3.8"
