Allow the Unicode-3.0 license

[siegfriedweber]

Allow the Unicode-3.0 license

This license is required after upgrading the dependencies with cargo update.

Without this entry in deny.toml, cargo deny check licenses throws the following error:

error[rejected]: failed to satisfy license requirements                                                                                                                       10:05:25 [26/996]
  ┌─ registry+https://github.com/rust-lang/crates.io-index#zerovec-derive@0.10.2:4:12
  │
4 │ license = "Unicode-3.0"
  │            ^^^^^^^^^^^
  │            │
  │            license expression retrieved via Cargo.toml `license`
  │            rejected: not explicitly allowed
  │
  = Unicode-3.0 - Unicode License v3:
  =   - OSI approved
  = zerovec-derive v0.10.2
    └── zerovec v0.10.2
        └── icu_collections v1.5.0
            └── icu_normalizer v1.5.0
                └── idna v1.0.0
                    └── url v2.5.1
                        └── stackable-operator v0.69.3 (*)

The license can be seen here: https://github.com/unicode-org/icu4x/blob/main/LICENSE