pkg/debian: Fix build dependencies

.github/workflows/debian.yml

@@ -29,8 +29,8 @@ jobs:
         ln -snf /usr/share/zoneinfo/$TZ /etc/localtime
         echo $TZ > /etc/timezone
         apt-get -y update
-        apt-get -y install build-essential fakeroot rsync git wget python3-debian dpkg-sig lz4 \
-            sbsigntool debhelper dpkg-dev zstd
+        apt-get -y install build-essential fakeroot rsync git wget python3-debian python-is-python3 \
+            zstd lz4 sbsigntool debhelper dpkg-dev dpkg-sig
         apt-get -y build-dep linux
 
     - name: Prepare kernel source