Update release.yml

use the proper requirements file to build the doc

.github/workflows/release.yml

@@ -62,7 +62,7 @@ jobs:
       - name: Install pyFAI
         run: pip install .
       - name: Install documentation dependencies
-        run: pip install -r requirements.txt
+        run: pip install -r ci/requirements_rtd.txt
       - name: Build doc
         env:
           READTHEDOCS: "True"  # To skip checking that pyFAI is installed locally