Fix Firefox upgradescenario

We don't want two versions of the addon to be installed at the same time,
because that won't work...

debian/control

@@ -80,7 +80,7 @@ Package: beid-mozilla-webext
 Section: web
 Architecture: all
 Depends: ${shlibs:Depends}, ${misc:Depends}, libbeidpkcs11-0, firefox (>= 58) | firefox-esr (>= 58)
-Conflicts: beid-mozilla-extension (<< 4.3.6)
+Conflicts: beid-mozilla-extension (<< 4.3.6), beid-mozilla-xpcext
 Replaces: beid-mozilla-extension (<< 4.3.6)
 Description: Belgian Electronic Identity Card - WebExtension
  This package contains the mozilla WebExtension-based addon for the
@@ -94,7 +94,7 @@ Description: Belgian Electronic Identity Card - WebExtension
 Package: beid-mozilla-xpcext
 Section: web
 Architecture: all
-Conflicts: beid-mozilla-extension (<< 4.3.6)
+Conflicts: beid-mozilla-extension (<< 4.3.6), beid-mozilla-webext
 Replaces: beid-mozilla-extension (<< 4.3.6)
 Depends: ${shlibs:Depends}, ${misc:Depends}, libbeidpkcs11-0, firefox (<< 57) | firefox-esr (<< 57)
 Description: Belgian Electronic Identity Card - XPCOM extension