Revert "want to test if the 1.20 really breaks this test"

This reverts commit 9dc8ae0.

Author: maksimov

.github/workflows/cluster_endtoend_vtctlbackup_sharded_clustertest_heavy.yml

@@ -44,7 +44,7 @@ jobs:
       if: steps.changes.outputs.end_to_end == 'true'
       uses: actions/setup-go@v4
       with:
-        go-version: '1.19'
+        go-version: '1.20'
         check-latest: true
 
     - name: Set up python