Possible improvements to `draft_release_notes.py`

[chrisbillowsMO]

We made some minor local changes to the draft_release_notes.py script and re-ran. Changes are now in: 63619a0e2.

We will open a new issue to improve this permanently.

--- a/esmvaltool/utils/draft_release_notes.py
+++ b/esmvaltool/utils/draft_release_notes.py
@@ -44,7 +44,7 @@ GITHUB_REPO = {
 TIMEZONE = ZoneInfo("CET")

 PREVIOUS_RELEASE = {
-    'esmvalcore': datetime.datetime(2023, 6, 6, 0, tzinfo=TIMEZONE),
+    'esmvalcore': datetime.datetime(2023, 12, 19, 18, tzinfo=TIMEZONE),
     'esmvaltool': datetime.datetime(2023, 6, 20, 0, tzinfo=TIMEZONE),
 }

@@ -62,11 +62,11 @@ LABELS = {
         'documentation',
         'fix for dataset',
         'installation',
-        'iris',
+        # 'iris',
         'preprocessor',
-        'release',
+        # 'release',
         'testing',
-        'UX',
+        # 'UX',
         'variable derivation',
         'enhancement',  # uncategorized, keep at the bottom
     ),

_Originally posted by @chrisbillowsMO in https://github.com/ESMValGroup/ESMValCore/pull/2414#discussion_r1598171116_

See also: https://github.com/ESMValGroup/ESMValCore/pull/2414#discussion_r1598184181

@bouweandela suggested using towncrier instead, see https://github.com/ESMValGroup/ESMValCore/discussions/2389#discussioncomment-9422069.