1.0.0

Why a major version: comparisons and parsing now follow semver.org 2.0.0 exactly. In 0.0.5
several of them were wrong. Fixing them changes the results of public API (<, ==, sorted(),
max(), Semantic(_:)), so code that sorts, compares or parses versions can see different
answers after upgrading. That is a breaking change, so the major version goes up. 1.0.0 is
also the first release with a stable public API.

The bugs were found by a TLA+ model of the library (formal/), and each one has a regression
test in Tests/MajorMinorPatchTests/SemverRegressionTests.swift.

Breaking: ordering (<, >, sorted(), min(), max())

Expression	0.0.5	1.0.0	Why (semver.org)
2.0.0 < 1.5.0	true (and 1.5.0 < 2.0.0 too)	false	11.2: compare major, then minor, then patch
2.0.0-alpha < 1.0.0	true	false	11.3: a pre-release only ranks below its own release
1.0.0 < 2.0.0-alpha	true	true	(unchanged)
1.0.0+a < 2.0.0+a	false both ways	true	10: build metadata is ignored for precedence
1.0.0-alpha+x < 1.0.0-beta	false	true	10 + 11.4
Identifier("a10") < Identifier("a2")	false (a2 < a10)	true	11.4.2: alphanumeric identifiers compare in ASCII order

Before, < was not a valid order (for example, both 2.0.0 < 1.5.0 and 1.5.0 < 2.0.0 were
true), so sorted() could return any order. It is now a strict weak order across all four
cases (.v, .vi, .vb, .vib).

Breaking: equality (==)

== now means same precedence: the version and pre-release are equal, and build metadata is
ignored. It is symmetric across cases.

Expression	0.0.5	1.0.0
1.0.0+build == 1.0.0	true	true
1.0.0 == 1.0.0+build	false	true
1.0.0-alpha == 1.0.0-alpha+build	true	true

To tell builds apart, compare metadata explicitly.

Breaking: parsing (Semantic(_:), Major(_:), Minor(_:), Patch(_:))

These strings parsed in 0.0.5 and now return nil:

Input	0.0.5	1.0.0	Why
01.0.0, 1.00.0, 1.0.01	parsed, printed without the zero (1.0.0)	nil	2: no leading zeroes
1.0.0-	parsed with empty identifiers; ==/< then crashed	nil	9: a pre-release needs one or more identifiers
1.0.0+	parsed with empty build metadata	nil	10: build metadata needs one or more identifiers

Unchanged

Valid semver strings parse and print as before. Major/Minor/Patch arithmetic,
incremented, decremented and the Identifier/Metadata validation rules are unchanged.

Migrating

• If you sort or compare versions, you need no code change; results are now correct. Re-check
  any stored ordering or snapshot built with 0.0.5.
• If you accepted user input with leading zeroes or a trailing -/+, handle the new nil
  (for example by normalising the input first).
• If you used == to mean "identical including build metadata", also compare metadata.