fix apt-get

.github/workflows/codeql-analysis.yml

@@ -12,12 +12,12 @@ on:
     # The branches below must be a subset of the branches above
     branches: [master]
   schedule:
-    - cron: '0 20 * * 3'
+    - cron: '0 14 * * 3'
 
 jobs:
   analyze:
     name: Analyze
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-18.04
 
     strategy:
       fail-fast: false
@@ -52,13 +52,9 @@ jobs:
         # queries: ./path/to/local/query, your-org/your-repo/queries@main
 
     - name: Install dependencies (Ubuntu 16 & 18)
-      if: startsWith(matrix.os, 'ubuntu') && matrix.os != 'ubuntu-20.04'
+      # Note: it's libzstd-dev in Ubuntu 20
       run: sudo apt-get install elfutils libzstd1-dev
 
-    - name: Install dependencies (Ubuntu 20)
-      if: matrix.os == 'ubuntu-20.04'
-      run: sudo apt-get install elfutils libzstd-dev
-
     # Autobuild attempts to build any compiled languages  (C/C++, C#, or Java).
     # If this step fails, then you should remove it and run the build manually (see below)
     - name: Autobuild