[Benchmark] Update gitaction as daily run

set gitaction - benchmark's daily run
- set cron '0 2 * * *'

**Self evaluation:**
1. Build test:	 [X]Passed [ ]Failed [ ]Skipped
2. Run test:	 [X]Passed [ ]Failed [ ]Skipped

Signed-off-by: Donghak PARK <donghak.park@samsung.com>

.github/workflows/ubuntu_benchmarks.yml

@@ -1,18 +1,16 @@
 name: Ubuntu Benchmarks
 
 on:
-#  schedule:
-#    - cron: '0 2 * * *'
-  pull_request:
-    types: [opened, edited, reopened, synchronize]
+  schedule:
+    - cron: '0 2 * * *'
 
 jobs:
   meson_test:
 
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: [ ubuntu-22.04 ]
+        os: [ ubuntu-20.04, ubuntu-22.04 ]
 
     steps:
     - uses: actions/checkout@v4