ci: run 'apt update' before installing packages

Author: ashenBlade

.github/workflows/testing.yml

@@ -62,6 +62,7 @@ jobs:
         cache: 'npm'
     - name: Setup environment
       run: |
+        sudo apt-get update
         sudo apt-get install -y build-essential wget gdb lldb libpq5
         echo 0 | sudo tee /proc/sys/kernel/yama/ptrace_scope
     - name: Restore PostgreSQL