Re-introduce a transitional apt-transport-https

This fixes issues with debootstrap. The package will disappear
after the release of buster.

debian/control

@@ -148,3 +148,12 @@ Description: package management related utility programs
   * apt-ftparchive is used to create Packages and other index files
     needed to publish an archive of Debian packages
   * apt-sortpkgs is a Packages/Sources file normalizer.
+
+Package: apt-transport-https
+Architecture: all
+Depends: apt (>= 1.5~alpha4)
+Priority: optional
+Section: oldlibs
+Description: transitional package for https support
+ This is a dummy transitional package - https support has been moved into
+ the apt package in 1.5. It can be safely removed.