Generate release notes using the new API

https://docs.github.com/en/rest/reference/repos#generate-release-notes-content-for-a-release

.github/workflows/releases.yml

@@ -16,10 +16,15 @@ jobs:
         with:
           go-version: 1.16
       - name: Generate changelog
+        id: changelog
         run: |
-          echo "GORELEASER_CURRENT_TAG=${GITHUB_REF#refs/tags/}" >> $GITHUB_ENV
-          git fetch --unshallow
-          script/changelog | tee CHANGELOG.md
+          echo "::set-output name=tag-name::${GITHUB_REF#refs/tags/}"
+          gh api repos/$GITHUB_REPOSITORY/releases/generate-notes \
+            -f tag_name="${GITHUB_REF#refs/tags/}" \
+            -f target_commitish=trunk \
+            -q .body > CHANGELOG.md
+        env:
+          GITHUB_TOKEN: ${{secrets.GITHUB_TOKEN}}
       - name: Run GoReleaser
         uses: goreleaser/goreleaser-action@v2
         with:
@@ -27,6 +32,7 @@ jobs:
           args: release --release-notes=CHANGELOG.md
         env:
           GITHUB_TOKEN: ${{secrets.GITHUB_TOKEN}}
+          GORELEASER_CURRENT_TAG: ${{steps.changelog.outputs.tag-name}}
       - name: Checkout documentation site
         uses: actions/checkout@v2
         with:

docs/releasing.md

@@ -1,6 +1,6 @@
 # Releasing
 
-Our build system automatically compiles and attaches cross-platform binaries to any git tag named `vX.Y.Z`. The automated changelog is generated from commit messages starting with “Merge pull request …” that landed between this tag and the previous one (as determined topologically by git).
+Our build system automatically compiles and attaches cross-platform binaries to any git tag named `vX.Y.Z`. The changelog is [generated from git commit log](https://docs.github.com/en/repositories/releasing-projects-on-github/automatically-generated-release-notes).
 
 Users who run official builds of `gh` on their machines will get notified about the new version within a 24 hour period.
 

script/changelog

@@ -1,24 +0,0 @@
-#!/bin/bash
-set -e
-
-current_tag="${GITHUB_REF#refs/tags/}"
-start_ref="HEAD"
-
-# Find the previous release on the same branch, skipping prereleases if the
-# current tag is a full release
-previous_tag=""
-while [[ -z $previous_tag || ( $previous_tag == *-* && $current_tag != *-* ) ]]; do
-  previous_tag="$(git describe --tags "$start_ref"^ --abbrev=0)"
-  start_ref="$previous_tag"
-done
-
-git log "$previous_tag".. --reverse --first-parent --oneline | \
-  while read -r sha title; do
-    if [[ $title == "Merge pull request #"* ]]; then
-      pr_num="$(grep -o '#[[:digit:]]\+' <<<"$title")"
-      pr_desc="$(git show -s --format=%b "$sha" | sed -n '1,/^$/p' | tr $'\n' ' ')"
-      printf "* %s %s\n\n" "$pr_desc" "$pr_num"
-    else
-      printf "* %s\n\n" "$title"
-    fi
-  done