Improve custom Renovate presets and pinning

[robo9k]

Seems like existing config is not working as intended

rust-magic-sys/.github/workflows/conventional-commits.yml

Lines 28 to 29 in a0ba329

	# renovate: taiki-e/install-action
	tool: cocogitto@6.0.0

https://crates.io/crates/cocogitto/versions

---

The version of release-plz is pinned within its action

rust-magic-sys/.github/workflows/release-plz.yml

Line 49 in a0ba329

version: "0.3.139"

But this uses a different format which is not compatible with the taiki-e/install-action regex
Since the action itself is pinning its binary, there's likely no need to pin it in our workflow

[robo9k]

Looks like Renovate does not properly use cargo semver

#193 v6 → v7 = major ✔️
#191 v0.4 → v0.5 = minor ❌

As per https://doc.rust-lang.org/cargo/reference/semver.html#change-categories

This guide uses the terms “major” and “minor” assuming this relates to a “1.0.0” release or later. Initial development releases starting with “0.y.z” can treat changes in “y” as a major release, and “z” as a minor release. “0.0.z” releases are always major changes. This is because Cargo uses the convention that only changes in the left-most non-zero component are considered incompatible.