ci: fix image tags indentation

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34532>
diff --git a/.gitlab-ci/image-tags.yml b/.gitlab-ci/image-tags.yml
index 6621c53..065c2c0 100644
--- a/.gitlab-ci/image-tags.yml
+++ b/.gitlab-ci/image-tags.yml
@@ -19,29 +19,29 @@
   - .gitlab-ci/conditional-build-image-tags.yml
 
 variables:
-   DEBIAN_BASE_TAG: "20250408-virgl"
+  DEBIAN_BASE_TAG: "20250408-virgl"
 
-   DEBIAN_BUILD_TAG: "20250324-android"
+  DEBIAN_BUILD_TAG: "20250324-android"
 
-   DEBIAN_TEST_ANDROID_TAG: "20250415-anglit"
-   DEBIAN_TEST_GL_TAG: "20250415-anglit"
-   DEBIAN_TEST_VK_TAG: "20250411-vkcts-main"
-   KERNEL_ROOTFS_TAG: "20250415-anglit"
+  DEBIAN_TEST_ANDROID_TAG: "20250415-anglit"
+  DEBIAN_TEST_GL_TAG: "20250415-anglit"
+  DEBIAN_TEST_VK_TAG: "20250411-vkcts-main"
+  KERNEL_ROOTFS_TAG: "20250415-anglit"
 
-   DEBIAN_PYUTILS_TAG: "20250321-s3cp-fix5"
+  DEBIAN_PYUTILS_TAG: "20250321-s3cp-fix5"
 
-   ALPINE_X86_64_BUILD_TAG: "20250324-sphinx"
-   ALPINE_X86_64_LAVA_SSH_TAG: "20250321-s3cp-fix5"
-   FEDORA_X86_64_BUILD_TAG: "20250321-s3cp-fix5"
+  ALPINE_X86_64_BUILD_TAG: "20250324-sphinx"
+  ALPINE_X86_64_LAVA_SSH_TAG: "20250321-s3cp-fix5"
+  FEDORA_X86_64_BUILD_TAG: "20250321-s3cp-fix5"
 
-   KERNEL_TAG: "v6.14-mesa-0bdd"
-   KERNEL_REPO: "gfx-ci/linux"
-   PKG_REPO_REV: "95bf62c"
+  KERNEL_TAG: "v6.14-mesa-0bdd"
+  KERNEL_REPO: "gfx-ci/linux"
+  PKG_REPO_REV: "95bf62c"
 
-   FLUSTER_VECTORS_VERSION: "5"
+  FLUSTER_VECTORS_VERSION: "5"
 
-   WINDOWS_X64_MSVC_TAG: "20250129-llvm19"
+  WINDOWS_X64_MSVC_TAG: "20250129-llvm19"
 
-   WINDOWS_X64_BUILD_TAG: "20250129-llvm19"
+  WINDOWS_X64_BUILD_TAG: "20250129-llvm19"
 
-   WINDOWS_X64_TEST_TAG: "20250129-llvm19"
+  WINDOWS_X64_TEST_TAG: "20250129-llvm19"