Get submodule in CI

.gitlab-ci.yml

@@ -11,6 +11,8 @@ build:
   image:
     name: avivace/iosevka-build
     entrypoint: [""]
+  variables:
+    GIT_SUBMODULE_STRATEGY: recursive
   script:
     - apt update -y
     - apt install -y zip xz-utils