chore(deps): update rust crate http-cache to 0.20.0

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
http-cache (source)	dev-dependencies	minor	0.18.0 -> 0.20.0

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Configuration

📅 Schedule: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined).

🚦 Automerge: Enabled.

♻ Rebasing: Whenever PR is behind base branch, or you tick the rebase/retry checkbox.

🔕 Ignore: Close this PR and you won't be reminded about this update again.

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• If you want to rebase/retry this PR, check this box

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[renovate]

⚠️ Artifact update problem

Renovate failed to update an artifact related to this branch. You probably do not want to merge this PR as-is.

♻ Renovate will retry this branch, including artifacts, only when one of the following happens:

• any of the package files in this branch needs updating, or
• the branch becomes conflicted, or
• you click the rebase/retry checkbox if found above, or
• you rename this PR's title to start with "rebase!" to trigger it manually

The artifact failure details are included below:

File name: Cargo.lock

Command failed: cargo update --config net.git-fetch-with-cli=true --manifest-path tailcall-http-cache/Cargo.toml --package http-cache@0.18.0 --precise 0.20.0
    Updating crates.io index
error: failed to select a version for the requirement `http-cache = "^0.18.0"`
candidate versions found which didn't match: 0.20.0
location searched: crates.io index
required by package `http-cache-reqwest v0.13.0`
    ... which satisfies dependency `http-cache-reqwest = "^0.13.0"` (locked to 0.13.0) of package `tailcall v0.1.0 (/tmp/renovate/repos/github/tailcallhq/tailcall)`

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