Add initial bp2build support for converting android_app_certificate modules.

Test: Added unit test.

Change-Id: Ib5bf1711eca5be772e1bed73663dcb86252e0b4a
diff --git a/bp2build/Android.bp b/bp2build/Android.bp
index 6ab062e..35f8c05 100644
--- a/bp2build/Android.bp
+++ b/bp2build/Android.bp
@@ -28,6 +28,7 @@
         "soong-sh",
     ],
     testSrcs: [
+        "android_app_certificate_conversion_test.go",
         "apex_conversion_test.go",
         "apex_key_conversion_test.go",
         "build_conversion_test.go",