Drop changelog date stamping and write release notes into the versions PR (#2998)

.github/workflows/release.yml

@@ -44,6 +44,29 @@ jobs:
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
 
+      # `changesets/action` fills the version pull request with one section per
+      # package (`## @tabler/core@1.5.1`, …), so a changeset that touches several
+      # packages shows up several times. Replace that body with the same notes the
+      # GitHub release gets: the intro from `.github/release-notes/<version>.md`
+      # and the changes grouped as core / demo / docs, each listed once. The
+      # action rewrites the body on every push to dev, so this runs right after it.
+      - name: Write the release notes into the version pull request
+        if: steps.changesets.outputs.pr-number != ''
+        continue-on-error: true
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          PR_NUMBER: ${{ steps.changesets.outputs.pr-number }}
+        run: |
+          git fetch --depth=1 origin changeset-release/dev
+          git checkout --force --detach origin/changeset-release/dev
+          version=$(node -p "require('./core/package.json').version")
+          {
+            echo "Merging this pull request publishes \`@tabler/core@${version}\` to npm and creates the GitHub release. It is regenerated on every push to \`dev\`."
+            echo
+            pnpm run --silent release-notes
+          } > "${RUNNER_TEMP}/pr-body.md"
+          gh pr edit "${PR_NUMBER}" --body-file "${RUNNER_TEMP}/pr-body.md"
+
       # `pnpm run build` above zipped preview/dist into packages-zip/; attach it to
       # the GitHub release that changesets/action just created for @tabler/core.
       - name: Attach the preview zip to the GitHub release