ci: move cache directive to global scope

Signed-off-by: Vojtěch Mareš <vojtech@mares.cz>

.gitlab-ci.yml

@@ -7,6 +7,11 @@ variables:
   PACKER_VAR_FILE: "vars.pkrvars.hcl"
   PACKER_CONFIG_DIR: $CI_PROJECT_DIR
 
+cache:
+  key: "packer-plugins"  # Define a key for Packer plugins
+  paths:
+    - "$PACKER_CONFIG_DIR/.packer.d"
+
 stages:
   - validate
   - build
@@ -25,10 +30,6 @@ validate:
     - packer init $PACKER_WORKSPACE
     - packer fmt -check $PACKER_WORKSPACE
     - packer validate $PACKER_WORKSPACE
-  cache:
-    key: "packer-plugins"  # Define a key for Packer plugins
-    paths:
-      - "$PACKER_CONFIG_DIR/.packer.d"
 
 build-image:
   extends: .parallel