dev: ci scheduled stale issue & pr check (monthly)

Author: practicalli-johnny

.github/workflows/scheduled-stale-check.yaml

@@ -12,7 +12,7 @@ name: 'Scheduled stale check'
 on:
   workflow_dispatch:
   schedule:
-    - cron: '30 1 * * *'
+    - cron: "0 1 1 * *" # at 01:00 on first day of month
 
 jobs:
   stale:

CHANGELOG.md

@@ -6,4 +6,5 @@
 - mkdocs: google analytics property identity
 - dev: standard GitHub workflow and MkDocs configuration
 - dev: url and path exclusions for spell lychee url check in megalinter
-- dev: `a` & `img` html elements allowed in markdown 
+- dev: `a` & `img` html elements allowed in markdown
+- dev: ci scheduled stale issue & pr check (monthly)