Incorrectly says some inputs are semver

[toddself]

When provided an input like a formatted date, this library incorrectly parses it as semver.

package main

import (
	"fmt"
	"regexp"
)

const (
	VersionRegexpRaw string = `v?([0-9]+(\.[0-9]+)*?)` +
		`(-([0-9]+[0-9A-Za-z\-~]*(\.[0-9A-Za-z\-~]+)*)|(-?([A-Za-z\-~]+[0-9A-Za-z\-~]*(\.[0-9A-Za-z\-~]+)*)))?` +
		`(\+([0-9A-Za-z\-~]+(\.[0-9A-Za-z\-~]+)*))?` +
		`?`

	// SemverRegexpRaw requires a separator between version and prerelease
	SemverRegexpRaw string = `v?([0-9]+(\.[0-9]+)*?)` +
		`(-([0-9]+[0-9A-Za-z\-~]*(\.[0-9A-Za-z\-~]+)*)|(-([A-Za-z\-~]+[0-9A-Za-z\-~]*(\.[0-9A-Za-z\-~]+)*)))?` +
		`(\+([0-9A-Za-z\-~]+(\.[0-9A-Za-z\-~]+)*))?` +
		`?`
)

// mostly from https://semver.org, but v added in front for npm compatibility
const validatingRE = `^[v]?(0|[1-9]\d*)\.(0|[1-9]\d*)\.(0|[1-9]\d*)(?:-((?:0|[1-9]\d*|\d*[a-zA-Z-][0-9a-zA-Z-]*)(?:\.(?:0|[1-9]\d*|\d*[a-zA-Z-][0-9a-zA-Z-]*))*))?(?:\+([0-9a-zA-Z-]+(?:\.[0-9a-zA-Z-]+)*))?$`

var semverOrgMatcher = regexp.MustCompile(validatingRE)

func main() {
	version := "2020-02-26T7-36-46"
	versionRegexp := regexp.MustCompile("^" + VersionRegexpRaw + "$")
	semverRegexp := regexp.MustCompile("^" + SemverRegexpRaw + "$")
	fmt.Println(versionRegexp.FindStringSubmatch(version))
	fmt.Println(semverRegexp.FindStringSubmatch(version))
	fmt.Println("is semver according to semver.org:", semverOrgMatcher.MatchString(version))
}

Go playground

I would have expected this to return an error about a malformed version rather than [2020-02-26T7-36-46 2020 -02-26T7-36-46 02-26T7-36-46 ]