fdroid: use swig from testing

Change-Id: I92a9a1c985549eeab3d030607a035fb539fa304f
Gitlab: #540
diff --git a/fdroidMergeRequest.sh b/fdroidMergeRequest.sh
index de822c0..e158bec 100755
--- a/fdroidMergeRequest.sh
+++ b/fdroidMergeRequest.sh
@@ -54,6 +54,9 @@
     timeout: 10800
     subdir: client-android/ring-android/app
     submodules: true
+    sudo:
+      - apt update || apt update
+      - apt install -y -t testing swig
     gradle:
       - noPush
     rm: