chore: allow for swift-syntax of 603.0.0

[Brett-Best]

📒 Description

Allows for Swift Syntax to resolve to 603.0.0.

🔍 Detailed Design

I fixed a deprecation warning and ensured compilation with Swift Syntax 600.0.0 still worked.

📓 Documentation Plan

N/A

🗳 Test Plan

Running the tests of the SwiftPM package it has against the My Mac target.

🧯 Source Impact

N/A

✅ Checklist

• I've added at least one test that validates that my change is working, if appropriate
• I've followed the code style of the rest of the project
• I've read the Contribution Guidelines
• I've updated the documentation if necessary

[Copilot]

Pull request overview

This PR updates the SwiftPM dependency constraint for swift-syntax to include 603.0.0, and adjusts the macro conformance to match the updated MemberMacro expansion signature required by newer SwiftSyntax releases.

Changes:

• Widen swift-syntax dependency range to allow resolving 603.x (by moving the upper bound to < 604.0.0).
• Update FlagContainerMacro’s MemberMacro.expansion signature to include the conformingTo parameter (addressing the deprecation / API shift in SwiftSyntax).

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
Sources/VexilMacros/FlagContainerMacro.swift	Updates MemberMacro expansion signature to include conformingTo protocols, aligning with newer SwiftSyntax macro APIs.
Package.swift	Expands the allowed swift-syntax version range to include 603.0.0.

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[Brett-Best]

@bok- if you could approve the workflows please, I'm fairly confident they should pass 🙏🏻

[bok-]

Thanks @Brett-Best! Looks good, lets get this in and I'll cut beta 2.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
1 Accepted issue

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarQube Cloud