Fix pre release check

Author: adonath

.github/workflows/release.yml

@@ -39,6 +39,8 @@ jobs:
       - name: Release
         uses: softprops/action-gh-release@v1
         with:
-          body_path: ${{ github.workspace }}/docs/release-notes/v1.1.rst
-          prerelease: contains(github.ref_name, "rc")
+          body: |
+            A Python package for gamma-ray astronomy. See [changelog for this release](https://github.com/adonath/gp-lts-workflow/blob/main/docs/release-notes/v1.1.rst)
+
+          prerelease: contains(github.ref_name, 'rc')