Fix failing pandoc command during release

Author: mkrnr

.github/RELEASE_DRAFT_FILTER.lua

@@ -10,13 +10,13 @@ return {
         release_count = release_count + 1
       end
       if elem.level < 3 or release_count > 1 then
-        return pandoc.Null()
+        return {}
       end
       return elem
     end,
     Block = function (elem)
       if release_count > 1 then
-        return pandoc.Null()
+        return {}
       end
       return elem
     end,

.github/workflows/ci/helpers.sh

@@ -179,7 +179,7 @@ EOF
   run pandoc --from=gfm --to=gfm \
     --lua-filter=.github/RELEASE_DRAFT_FILTER.lua \
     --template=.github/RELEASE_DRAFT_TEMPLATE.md \
-    --base-header-level=2 --wrap=none \
+    --shift-heading-level-by=2 --wrap=none \
     --variable="version:$RELEASE_VERSION" \
     --output=notes.md \
     "$notes_body" || die

.gitignore

@@ -16,6 +16,7 @@
 
 # Plover: build artifacts.
 news_draft.md
+notes.md
 
 # Pytest.
 /.pytest_cache/