Update release workflow

Author: fingolfin

.github/workflows/release.yml

@@ -1,3 +1,6 @@
+# This workflow is responsible for making releases of this GAP package,
+# and updating its website afterwards. For usage instructions, see
+# <https://github.com/gap-actions/release-pkg/>.
 name: Release
 
 on:
@@ -24,6 +27,8 @@ jobs:
     steps:
       - uses: actions/checkout@v6
       - uses: gap-actions/setup-gap@v3
+        with:
+          gap-version: 'devel'
       - uses: gap-actions/build-pkg-docs@v2
         with:
           use-latex: true