travis: test debian stable

Author: avsm

.travis.yml

@@ -15,6 +15,6 @@ env:
   - PACKAGE="cstruct"       DISTRO="alpine"   OCAML_VERSION="4.07"
   - PACKAGE="cstruct-lwt"   DISTRO="debian-testing"  OCAML_VERSION="4.07"
   - PACKAGE="cstruct-async" DISTRO="centos"   OCAML_VERSION="4.07"
-  - PACKAGE="ppx_cstruct"   DISTRO="debian-unstable" OCAML_VERSION="4.07"
+  - PACKAGE="ppx_cstruct"   DISTRO="debian-stable" OCAML_VERSION="4.07"
   - PACKAGE="cstruct-unix"  DISTRO="ubuntu"          OCAML_VERSION="4.07"
   - PACKAGE="cstruct-unix"  DISTRO="alpine"          OCAML_VERSION="4.08"