Update main.yml

Author: rahlk

.github/workflows/main.yml

@@ -14,6 +14,9 @@ jobs:
       PATH: ${{ github.workspace }}/graalvm-community-openjdk-17.0.9+9.1/bin:$PATH
 
     steps:
+      - name: Install tar (if necessary)
+        run: sudo apt-get update && sudo apt-get install -y tar
+
       - name: Check out code
         uses: actions/checkout@v2