fix nightly release bash script (#1224)

Signed-off-by: Keming <[email protected]>

.github/workflows/nightly.yml

@@ -22,11 +22,16 @@ jobs:
           fetch-depth: 0
       - if: ${{ github.event_name == 'workflow_dispatch' }}
         run: |
+          gh release delete ${{ github.event.inputs.tag_name }} --yes --cleanup-tag || true
+          git tag -d ${{ github.event.inputs.tag_name }}
           gh release create ${{ github.event.inputs.tag_name }} --title ${{ github.event.inputs.tag_name }} --generate-notes --prerelease
 
       - if: ${{ github.event_name == 'schedule' }}
         run: |
-          if [[ $(git diff nightly --name-only -B -M -C) ]]; then
+          if [[ -z $(git tag -l nightly) ]]; then
+            gh release create nightly --title nightly --generate-notes --prerelease
+          elif [[ $(git diff nightly --name-only -B -M -C) ]]; then
             gh release delete nightly --yes --cleanup-tag || true
+            git tag -d nightly
             gh release create nightly --title nightly --generate-notes --prerelease
           fi