Add the `multi_arch` option in make_deb.py in order to add the `Multi-Arch` field in debian control file. (#937)

pkg/private/deb/make_deb.py

diff --git a/pkg/private/deb/make_deb.py b/pkg/private/deb/make_deb.py
index 9d10c4b..84748c5 100644
--- a/pkg/private/deb/make_deb.py
+++ b/pkg/private/deb/make_deb.py
@@ -59,6 +59,7 @@
     ('Built-Using', False, False, None),
     ('Distribution', False, False, 'unstable'),
     ('Urgency', False, False, 'medium'),
+    ('Multi-Arch', False, False),
 ]
 
 # size of chunks for copying package content to final .deb file
@@ -407,7 +408,9 @@
       priority=options.priority,
       conflicts=options.conflicts,
       breaks=options.breaks,
-      installedSize=helpers.GetFlagValue(options.installed_size))
+      installedSize=helpers.GetFlagValue(options.installed_size),
+      multiArch=helpers.GetFlagValue(options.multi_arch)
+  )
   CreateChanges(
       output=options.changes,
       deb_file=options.output,