Consider .capex files as zip archives am: 6ac9005918

Original change: https://googleplex-android-review.googlesource.com/c/platform/system/update_engine/+/15829227

Change-Id: I2cb2849e061453ce1fed2c1cbbf92b52aad441be
diff --git a/payload_generator/deflate_utils.cc b/payload_generator/deflate_utils.cc
index c874bfd..68d44d7 100644
--- a/payload_generator/deflate_utils.cc
+++ b/payload_generator/deflate_utils.cc
@@ -312,7 +312,7 @@
       // .zvoice files may eventually move out of rootfs. If that happens,
       // remove ".zvoice" (crbug.com/782918).
       bool is_zip = IsFileExtensions(
-          file.name, {".apk", ".zip", ".jar", ".zvoice", ".apex"});
+          file.name, {".apk", ".zip", ".jar", ".zvoice", ".apex", "capex"});
       bool is_gzip = IsFileExtensions(file.name, {".gz", ".gzip", ".tgz"});
       if (is_zip || is_gzip) {
         brillo::Blob data;