Fix the write hint in Vault pack
Fix the write hint in Vault pack

The `vault.write` action requires double-quoted parameters, changing
the hint accordingly.

pidah/st2contrib,StackStorm/st2contrib,tonybaloney/st2contrib,pearsontechnology/st2contrib,tonybaloney/st2contrib,pearsontechnology/st2contrib,pidah/st2contrib,armab/st2contrib,armab/st2contrib,pearsontechnology/st2contrib,pidah/st2contrib,armab/st2contrib,StackStorm/st2contrib,pearsontechnology/st2contrib,StackStorm/st2contrib,tonybaloney/st2contrib