Fix GitHub Actions: Remove md5sum package installation

- md5sum is part of coreutils which is already installed on Ubuntu
- Removed unnecessary package installation that was causing errors
- GitHub Actions should now run successfully

Author: akintunero

.github/workflows/test.yml

@@ -29,7 +29,8 @@ jobs:
     - name: Install dependencies
       run: |
         # Install additional tools
-        sudo apt-get install -y md5sum
+        # md5sum is part of coreutils, which is already installed
+        # No additional installation needed
         
     - name: Run shellcheck
       run: |