Add GitLab deployment instructions

Not tested in anger but looks like it should work! Hoping our friends at
GitLab can give the final verdict.

docs/deploying.md

@@ -26,7 +26,7 @@ jobs:
       - run:
           name: Install catalog-importer
           command: |
-            VERSION="1.7.0"
+            VERSION="2.4.3"
 
             echo "Installing importer v${VERSION}..."
             curl -L \
@@ -78,7 +78,7 @@ jobs:
           go-version: "1.20"
       - name: Install catalog-importer
         run: |
-          VERSION="1.7.0"
+          VERSION="2.4.3"
 
           echo "Installing importer v${VERSION}..."
           curl -L \
@@ -88,5 +88,51 @@ jobs:
       - name: Sync
         run: |
           /tmp/catalog-importer sync --config=importer.jsonnet --prune
+
 ```
 
+## GitLab CI
+
+If you run on GitLab CI, an example config is:
+
+```yaml
+# .gitlab-ci.yml
+
+variables:
+  IMPORTER_VERSION: "2.4.3"
+
+sync:
+  image: ubuntu:latest
+
+  # You can use rules to control when the job runs
+  rules:
+    # Run on every push to any branch
+    - if: $CI_COMMIT_BRANCH
+      when: always
+
+    # Alternatively, you can use scheduled pipelines
+    # Configure this in GitLab UI: Settings > CI/CD > Pipeline schedules
+    # - if: $CI_PIPELINE_SOURCE == "schedule"
+    #   when: always
+
+  before_script:
+    # Install curl and other dependencies
+    - apt-get update && apt-get install -y curl
+
+    # Install catalog-importer
+    - |
+      echo "Installing importer v${IMPORTER_VERSION}..."
+      curl -L \
+        -o "/tmp/catalog-importer_${IMPORTER_VERSION}_linux_amd64.tar.gz" \
+        "https://github.com/incident-io/catalog-importer/releases/download/v${IMPORTER_VERSION}/catalog-importer_${IMPORTER_VERSION}_linux_amd64.tar.gz"
+      tar zxf "/tmp/catalog-importer_${IMPORTER_VERSION}_linux_amd64.tar.gz" -C /tmp
+
+  script:
+    # Run sync with different options based on branch
+    - |
+      if [ "$CI_COMMIT_BRANCH" = "master" ] || [ "$CI_COMMIT_BRANCH" = "main" ]; then
+        /tmp/catalog-importer sync --config importer.jsonnet --prune
+      else
+        /tmp/catalog-importer sync --config importer.jsonnet --dry-run
+      fi
+```