[librsvg] gitlabci: Add test for rustc v1.25

[Jordan Petridis <jpetridis src gnome org>]

commit 7a3ae3f6602cd6af003ecc8a667b60f3d1a816b8
Author: Jordan Petridis <jordanpetridis protonmail com>
Date:   Thu Mar 29 13:38:11 2018 +0300

    gitlabci: Add test for rustc v1.25

 .gitlab-ci.yml | 8 ++++++++
 1 file changed, 8 insertions(+)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index de9918da..35e38848 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -16,6 +16,7 @@ variables:
   RUSTC_1_22:                "registry.gitlab.com/alatiera/librsvg-oci-images/rustc:1.22"
   RUSTC_1_23:                "registry.gitlab.com/alatiera/librsvg-oci-images/rustc:1.23"
   RUSTC_1_24:                "registry.gitlab.com/alatiera/librsvg-oci-images/rustc:1.24"
+  RUSTC_1_25:                "registry.gitlab.com/alatiera/librsvg-oci-images/rustc:1.25"
 
   RUSTFMT_NIGHTLY:           "registry.gitlab.com/alatiera/rustfmt-oci-image/rustfmt:nightly"
   CLIPPY_NIGHTLY:            "registry.gitlab.com/alatiera/librsvg-oci-images/clippy:nightly"
@@ -245,3 +246,10 @@ rustc:1_24:
     LIBRSVG_DEBUG: "yes"
   <<: *rustc
   <<: *stage_3
+
+rustc:1_25:
+  image: $RUSTC_1_25
+  variables:
+    LIBRSVG_DEBUG: "yes"
+  <<: *rustc
+  <<: *stage_3