chore(release): date 0.9.0

[jonyoder]

Dates [Unreleased] as 0.9.0 (2026-08-28) and adds its compare link. CHANGELOG only; no code changes.

Verified against git diff v0.8.0..origin/main -- CHANGELOG.md that the section contains exactly the two subheadings added since that tag (Added, Fixed) and removes none, so no already-published content is re-dated.

Why a minor bump

Under the 0.x policy at the top of the file, two of these changes alter observable behaviour rather than only adding surface:

• reqtxt now recognizes --all-releases, --only-final and --use-feature. Previously an unrecognized option was assumed boolean, so its argument was dispatched as its own line and became a fabricated requirement — --use-feature 2020-resolver produced a package named 2020-resolver from a valid pip file.
• A standalone --hash line is accepted rather than rejected, matching pip, which logs that it will be ignored and continues.

Neither is a compile-time break, but both change what a caller gets from an unchanged input file, which is what the Breaking-in-a-minor policy exists to signal.

Contents since v0.8.0

Area	Change	Issue / PR
tags	riscv64/loongarch64 floored at glibc 2.17 with the manylinux2014 alias, matching packaging (42 tags → 393/582)	#42, #43
marker	EvaluateUndecidable and Variables, so a caller can distinguish "false" from "could not decide"	#44, #47
tags	IsCompatibleOrNewer, CompileAnyLibc, Archs/OSes	#45, #48
reqtxt	Source on every entry and option, plus three pip-parity fixes	#46, #49
deps	testify 1.12.1, x/text 0.41.0, x/crypto 0.55.0	#50

Verification

gofmt clean, go vet ./... clean, full module suite green including the packaging-generated golden fixtures and the ported PEP 440/508 conformance suites.

Posit Package Manager is the consumer waiting on this: its PyPI dependency-closure work cannot vendor until there is a tag.

🤖 Generated with Claude Code