fixed the fixed if syntax

Author: chenkasirer

action.yml

@@ -18,7 +18,7 @@ runs:
     - run: |
         command="ipy ${{ github.action_path }}/componentize.py ${{ inputs.source }} ${{ inputs.target }} --ghio ./lib"
         prefix="${{ inputs.prefix }}"      
-        if [ -n "$prefix" ]; then
+        if [[ -n "$prefix" ]]; then
           command="$command --prefix $prefix"
         fi
         $command