Use array instead of string, also pass in args to python3 instead of entire command

Author: Pocketkid2

edalize/tools/vpr.py

@@ -118,15 +118,15 @@ def configure(self, edam):
             depends = self.name + ".net"
             targets = gen_constr_list[0]
             commands.add(
-                gen_constr_list[2],
+                ["python3", gen_constr_list[2]],
                 [targets],
                 [depends],
             )
 
             depends = gen_constr_list[0]
             targets = gen_constr_list[1]
             commands.add(
-                gen_constr_list[3],
+                ["python3", gen_constr_list[3]],
                 [targets],
                 [depends],
             )