try to fix prerelease conditional part 2 (#15)

.github/workflows/pypi-publish-workflow.yml

@@ -28,7 +28,7 @@ jobs:
         git config --global user.email '[email protected]'
         pdm bump tag && git push --tags
         tag=$( pdm show --version )
-        tag_is_full_release=$( test "${tag}" "=~" "^v[0-9]+.[0-9]+.[0-9]+\$" && echo 'TRUE' || echo 'FALSE' )
+        tag_is_full_release=$( [[ "${tag}" =~ ^v[0-9]+\.[0-9]+\.[0-9]+\$ ]] && echo 'TRUE' || echo 'FALSE' )
         echo "tag=${tag}" >> "$GITHUB_OUTPUT"
         echo "full-release=${tag_is_full_release}"
     - name: Test and get reports