tftarget doesn't properly escape quotation marks

Resource paths using a quotation mark, e.g. `module.xyz.aws_iam_user_group_membership.smtp-user-membership["abc"]`, do not work, but yield the error

```
│ Error: Invalid target "module.xyz.aws_iam_user_group_membership.smtp-user-membership[abc]"
│
│ Index brackets must contain either a literal number or a literal string.
```