Update sphinx in environment.yml

Author: sebp

environment.yml

@@ -2,13 +2,13 @@ name: rtd
 channels:
   - defaults
 dependencies:
-  - python=3.9
+  - python=3.12
   - gettext
-  - Jinja2<3.1.0
+  - Jinja2>=3.1.3,<3.2
   - mock
   - pillow
   - pip
-  - sphinx<4
-  - sphinx_rtd_theme<2
+  - sphinx>=7.3.7,<7.4
+  - sphinx_rtd_theme>=2.0.0,<2.1
   - pip:
-    - sphinx-intl
+    - sphinx-intl>=2.2.0,<2.3