Add support for workspace inheritance in Cargo.toml

[0xf333]

Description:

Currently, when trying to use the {key}.workspace syntax in Cargo.toml to inherit package metadata and dependencies from the workspace, cargo-contract fails to parse the manifest.

Impact:

This feature is particularly useful for projects with multiple packages that share common configurations and dependencies as it's the case for Ink-examples.
Supporting this feature would streamline the development process and reduce redundancy in Cargo.toml files.

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Steps to Reproduce:

1. Clone the repository:

git clone https://github.com/0xf333/test_scenario.git

2. Navigate to the call_one or call_two directory:

cd call_one

3. Run the following command:

cargo contract build --release

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Expected Behavior:

The contract should be built successfully by inheriting the necessary configurations and dependencies from the workspace.

Actual Behavior:

The build process fails with an error related to parsing the manifest.

`cargo metadata` exited with an error: failed to parse manifest

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Environment:

• OS: Debian
• cargo-contract version 3.0.1
• ink! version: 4.2.0

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Additional context:

This issue seems specific to cargo-contract as the standard Cargo toolchain supports this feature.