chore(release): prepare release 1.18.0 - #11003

This PR prepares the release 1.18.0.

Summary by cubic

Prepares the axios 1.18.0 release by updating version metadata in package.json, package-lock.json, and lib/env/data.js (VERSION). No functional changes.

Description

• Summary of changes

  • Bump version in package.json and package-lock.json to 1.18.0.
  • Update lib/env/data.js to export VERSION = "1.18.0".

• Reasoning

  • Align runtime-reported version with npm metadata for the 1.18.0 release.

• Additional context

  • Release prep only; no API or behavior changes.

Docs

• Add a 1.18.0 entry in /docs/ (release notes/changelog).
• Update any version badges or examples referencing 1.17.0.

Testing

• No tests added. Change is metadata-only.
• Suggested check: build and verify reported version is 1.18.0.

Semantic version impact

• Minor: releasing 1.18.0; this PR itself does not introduce breaking changes.

^{Written for commit 93170cf. Summary will update on new commits.}