#145 Migrating FP_PDN_MACRO_HOOKS Issue created by kareefardi

"PDN_MACRO_CONNECTIONS": "mprj vccd1 vssd1 vccd1 vssd1"

will generate an error mid flow. The error message is not very useful. The fix is to make it

"PDN_MACRO_CONNECTIONS": ["mprj vccd1 vssd1 vccd1 vssd1"]

efabless/openlane2