fix(vdev): release prepare vrl version pinning

[thomasqueirozb]

Summary

Added --dry-run to release prepare and also fixed vrl pinning.

Vector configuration

NA

How did you test this PR?

release-new.env

#!/usr/bin/env bash
export NEW_VECTOR_VERSION=0.52.0 # replace this with the actual new version (e.g.: 0.50.0)
export NEW_VRL_VERSION=0.28.0 # replace this with the actual new VRL version (e.g.: 0.30.0)
export MINOR_VERSION=$(echo "$NEW_VECTOR_VERSION" | cut -d. -f2)
export PREP_BRANCH=prepare-v-"${NEW_VECTOR_VERSION//./-}"-website
export RELEASE_BRANCH=v0."${MINOR_VERSION}"

---

source release-new.env
cargo vdev -vvvv release prepare --version "${NEW_VECTOR_VERSION}" --vrl-version "${NEW_VRL_VERSION}" --dry-run

Change Type

• Bug fix
• New feature
• Non-functional (chore, refactoring, docs)
• Performance

Is this a breaking change?

• Yes
• No

Does this PR include user facing changes?

• Yes. Please add a changelog fragment based on our guidelines.
• No. A maintainer will apply the no-changelog label to this PR.

[datadog-vectordotdev]

✅ Tests

🎉 All green!

❄️ No new flaky tests detected
🧪 All tests passed

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