apt: deb822 migration python script is looked relative to shell script

CHANGELOG.md

@@ -17,7 +17,8 @@ The **patch** part changes is incremented if multiple releases happen the same m
 
 ### Changed
 
-minifirewall: support protocols in numeric form
+* apt: deb822 migration python script is looked relative to shell script
+* minifirewall: support protocols in numeric form
 
 ### Fixed
 

apt/files/deb822-migration.sh

@@ -3,7 +3,7 @@
 deb822_migrate_script=$(command -v deb822-migration.py)
 
 if [ -z "${deb822_migrate_script}" ]; then
-    deb822_migrate_script="./deb822-migration.py"
+    deb822_migrate_script="$(dirname "$0")/deb822-migration.py"
 fi
 if [ ! -x "${deb822_migrate_script}" ]; then
     >&2 echo "ERROR: '${deb822_migrate_script}' not found or not executable"