chore: Move to melos 7.0.0-dev.3

[spydon]

Description

This moves us to Melos 7.0.0-dev.3 and thus removes the root melos.yaml file.

Checklist

• I have followed the Contributor Guide when preparing my PR.
• I have updated/added tests for ALL new/updated/fixed functionality.
• I have updated/added relevant documentation in docs and added dartdoc comments with ///.
• I have updated/added relevant examples in examples or docs.

Breaking Change?

• Yes, this PR is a breaking change.
• No, this PR is not a breaking change.

Related Issues

[github-actions]

Benchmark Results

Package flame:

Benchmarks	Current Branch [chore/move-to-melos-7.0.0-dev.3]	Base Branch [main]	Diff
Render Components Benchmark	1163.896 μs	1172.598 μs	🟢 -0.742 %
Updating Components Benchmark	257025.375 μs	254148.250 μs	🔴 +1.132 %

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Benchmarks provided with 💙 by Dart Benchmark Action.