ci: reduce rocksdb-cache execiton frequence (backport #22193) (#22199)

Co-authored-by: auricom <27022259+auricom@users.noreply.github.com>

.github/workflows/cache-rocksdb.yml

@@ -4,7 +4,7 @@ on:
     paths:
       - build.mk
   schedule:
-    - cron: "*/15 * * * *" # Every 15 minutes
+    - cron: "15 */2 * * *" # Every two hours at xx:15 minutes
   workflow_dispatch:
 
 permissions:
@@ -59,4 +59,4 @@ jobs:
           path: |
             /usr/local/lib/librocksdb.*
             /usr/local/include/rocksdb
-          key: ${{ runner.os }}-rocksdb-${{ env.ROCKSDB_VERSION }}-amd64
+          key: ${{ runner.os }}-rocksdb-${{ env.ROCKSDB_VERSION }}-amd64