[forc-pkg] fix forc-pkg registry builds only support exact versions

[kayagokalp]

Currently (as of #7038) we only support exact version pins like x.y.z, but we do want to support things like carets (std = "^0.56") and wildcards (std = "*"). This has two parts:

1. Actually accept this form in manifest file
2. And resolve carets and wildcards according to their logic (if wildcard use latest or if caret use latest but adhere to the limitation described in the version declaration)