Bump required python version to 3.9 in stdeb.cfg

stdeb.cfg

@@ -6,6 +6,6 @@ Suite: focal
 Suite3: focal
 Build-Depends: debhelper, dh-python, python3-all, python3-pip, python3-setuptools, python3-wheel, python3-stdeb
 Depends3: nodejs, wget, curl, git, ffmpeg, youtube-dl, yt-dlp, python3-all, python3-pip, python3-setuptools, python3-croniter, python3-crontab, python3-dateparser, python3-django, python3-django-extensions, python3-django-jsonfield, python3-mypy-extensions, python3-requests, python3-w3lib, ripgrep
-X-Python3-Version: >= 3.7
-XS-Python-Version: >= 3.7
+X-Python3-Version: >= 3.9
+XS-Python-Version: >= 3.9
 Setup-Env-Vars: DEB_BUILD_OPTIONS=nocheck