cirrus: Only cache releases when needed

This does not change behavior, but removes unneeded and empty cache
instructions for tasks that don't need them.

Author: MarcoFalke

.cirrus.yml

@@ -35,8 +35,6 @@ global_task_template: &GLOBAL_TASK_TEMPLATE
     folder: "/tmp/cirrus-ci-build/depends/built"
   depends_sdk_cache:
     folder: "/tmp/cirrus-ci-build/depends/sdk-sources"
-  depends_releases_cache:
-    folder: "/tmp/cirrus-ci-build/releases"
   ci_script:
     - ./ci/test_run_all.sh
 
@@ -103,6 +101,8 @@ task:
   # For faster CI feedback, immediately schedule a task that compiles most modules
   << : *CREDITS_TEMPLATE
   << : *GLOBAL_TASK_TEMPLATE
+  depends_releases_cache:
+    folder: "/tmp/cirrus-ci-build/releases"
   container:
     image: ubuntu:bionic
   env: