btrfs-progs: docs: add config file for readthedocs.io

There's another config required for building the RTD documentation,
https://docs.readthedocs.io/en/stable/config-file/ .

[ci skip]

Signed-off-by: David Sterba <dsterba@suse.com>

.gitignore

@@ -73,6 +73,7 @@
 .*
 !.editorconfig
 !.github
+!.readthedocs.yaml
 
 /ci/images/*/devel.tar.gz
 

.readthedocs.yaml

@@ -0,0 +1,10 @@
+version: 2
+build:
+  os: ubuntu-22.04
+  tools:
+    python: "3.12"
+sphinx:
+  configuration: Documentation/conf.py
+python:
+  install:
+    - requirements: Documentation/requirements.txt

Documentation/conf.py

@@ -71,3 +71,5 @@ man_pages = [
     ('mkfs.btrfs', 'mkfs.btrfs', 'create a btrfs filesystem', '', 8),
     ('btrfs-man5', 'btrfs', 'topics about the BTRFS filesystem (mount options, supported file attributes and other)', '', 5),
 ]
+
+extensions = [ 'sphinx_rtd_theme' ]

Documentation/requirements.txt

@@ -0,0 +1 @@
+sphinx_rtd_theme