Refine release preparation step

* use release artifact URL for WORKSPACE snippet
* add bzlmod MODULE.bazel snippet to release body

Author: avdv

.github/workflows/prepare-release.yaml

@@ -12,12 +12,6 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v4
-      - name: Prepare workspace snippet
-        run: .github/workflows/workspace_snippet.sh > release_notes.txt
-      - name: Generate changelog
-        run: |
-          printf '\n-----\n\n' >> release_notes.txt
-          awk -f .github/workflows/changelog.awk CHANGELOG.md >> release_notes.txt
       - name: Create archive
         id: archive
         run: |
@@ -29,6 +23,12 @@ jobs:
           echo "tgz=${ARCHIVE}" >> $GITHUB_OUTPUT
 
           git archive --format=tar.gz --prefix="${PREFIX}/" -o "$ARCHIVE" "${TAG}"
+      - name: Prepare workspace snippet
+        run: .github/workflows/workspace_snippet.sh ${{ steps.archive.outputs.tgz }} > release_notes.txt
+      - name: Generate changelog
+        run: |
+          printf '\n-----\n\n' >> release_notes.txt
+          awk -f .github/workflows/changelog.awk CHANGELOG.md >> release_notes.txt
       - name: Release
         uses: softprops/action-gh-release@v1
         with:

.github/workflows/workspace_snippet.sh

@@ -2,20 +2,32 @@
 
 set -o errexit -o nounset -o pipefail
 
+ARCHIVE="$1"
+
 # Set by GH actions, see
 # https://docs.github.com/en/actions/learn-github-actions/environment-variables#default-environment-variables
 TAG=${GITHUB_REF_NAME}
 REPO_NAME=${GITHUB_REPOSITORY#*/}
 PREFIX="${REPO_NAME}-${TAG:1}"
-URL="https://github.com/${GITHUB_REPOSITORY}/archive/refs/tags/${TAG}.tar.gz"
+URL="https://github.com/${GITHUB_REPOSITORY}/releases/download/$TAG/$ARCHIVE"
 
-if ! SHA=$( curl -sfL "${URL}" | shasum -a 256 | awk '{print $1}'); then
-    echo "error: could not determine hash for ${URL}" >&2
+if ! SHA=$( shasum -a 256 "$ARCHIVE" | awk '{print $1}'); then
+    echo "error: could not determine hash for ${ARCHIVE}" >&2
     exit 1
 fi
 
 cat << EOF
-WORKSPACE snippet:
+## Using bzlmod with Bazel 6
+
+1. Enable with \`common --enable_bzlmod\` in \`.bazelrc\`.
+2. Add to your \`MODULE.bazel\` file:
+
+\`\`\`starlark
+bazel_dep(name = "rules_haskell", version = "${TAG:1}")
+\`\`\`
+
+## Using WORKSPACE
+
 \`\`\`starlark
 load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
 http_archive(