Enhance release notes automation (#3751) (#3776)

* Bump versions
* It now tabs every line included in the Release Notes section of
  the PR template

(cherry picked from commit b00b22a)

# Conflicts:
#	.github/workflows/config/release-notes.json
#	.github/workflows/release-notes.yml

Co-authored-by: Jack Koenig <koenig@sifive.com>

.github/workflows/config/release-notes.json

@@ -0,0 +1,86 @@
+{
+    "categories": [
+      {
+        "title": "## Features",
+        "labels": ["Feature"]
+      },
+      {
+        "title": "## API Modification",
+        "labels": ["API Modification"]
+      },
+      {
+        "title": "## API Deprecation",
+        "labels": ["Deprecation"]
+      },
+      {
+        "title": "## Backend Code Generation",
+        "labels": ["Backend Code Generation"]
+      },
+      {
+        "title": "## Performance",
+        "labels": ["Performance"]
+      },
+      {
+        "title": "## Fixes",
+        "labels": ["Bugfix"]
+      },
+      {
+        "title": "## Documentation",
+        "labels": ["Documentation"]
+      },
+      {
+        "title": "## Dependency Updates",
+        "labels": ["Dependency Update"]
+      },
+      {
+        "title": "## Build and Internal Changes",
+        "labels": ["Internal"]
+      },
+      {
+        "title": "## Uncategorized",
+        "labels": []
+      }
+    ],
+    "ignore_labels": [
+      "No Release Notes"
+    ],
+    "sort": {
+      "order": "ASC",
+      "on_property": "mergedAt"
+    },
+    "template": "${{CHANGELOG}}\n\n**Full Changelog:** ${{RELEASE_DIFF}}\n",
+    "pr_template": "- ${{TITLE}} (by @${{AUTHOR}} in ${{URL}})${{RELEASE_NOTES}}",
+    "empty_template": "- no changes",
+    "transformers": [
+      {
+        "pattern": "<!--.*-->",
+        "flags": "gus",
+        "target": ""
+      },
+      {
+        "pattern": "\n\\s*\n",
+        "flags": "gu",
+        "target": "\n"
+      },
+      {
+        "pattern": "\n",
+        "flags": "gu",
+        "target": "\n  "
+      }
+    ],
+    "custom_placeholders": [
+      {
+        "name": "RELEASE_NOTES",
+        "source": "BODY",
+        "transformer": {
+          "pattern": ".*#### Release Notes(?:[\n\\s]|(?:<!--.*?-->))*((?:\\S(?!!--)).*?)[\n\\s]*\n#.*",
+          "flags": "gus",
+          "target": "\n$1"
+        }
+      }
+    ],
+    "trim_values": false,
+    "max_tags_to_fetch": 200,
+    "max_pull_requests": 1000,
+    "max_back_track_time_days": 365
+}

.github/workflows/release-notes.yml

@@ -0,0 +1,50 @@
+name: Generate Release Notes
+
+on:
+  release:
+    types: [created]
+  workflow_dispatch:
+    inputs:
+      toTag:
+        description: 'Tag or ref for which to generate release notes'
+        required: true
+      fromTag:
+        # If you leave this blank, it'll select previous SemVer version
+        # WARNING: Cannot use anything older than a005498 because of the git tree merge
+        description: 'Tag or ref from which to start generating release notes'
+        required: false
+
+
+jobs:
+  generate_release_notes:
+    name: Generate Release Notes
+    runs-on: ubuntu-22.04
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      - name: Build Release Notes
+        id: release-notes
+        uses: mikepenz/release-changelog-builder-action@v4.1.1
+        with:
+          configuration: .github/workflows/config/release-notes.json
+          failOnError: true
+          # Amazingly, on release where the inputs are empty, this just does the right thing
+          # The "toTag" is the released tag, and the "fromTag" is the previous tag according to SemVer
+          fromTag: ${{ github.event.inputs.fromTag }}
+          toTag: ${{ github.event.inputs.toTag }}
+          token: ${{ secrets.GITHUB_TOKEN }}
+      - name: Report Release Notes
+        # Put output through env variable to make it robust to quotes
+        env:
+          CHANGELOG: ${{steps.release-notes.outputs.changelog}}
+        run: echo "$CHANGELOG" >> $GITHUB_STEP_SUMMARY
+      - name: Upload Release Notes (on release)
+        if: github.event_name == 'release'
+        uses: softprops/action-gh-release@v0.1.15
+        with:
+          body: ${{ steps.release-notes.outputs.changelog }}
+      - name: Error on uncategorized PRs
+        if: steps.release-notes.outputs.uncategorized_prs != 0
+        run: exit 1
+