Set SemverCompatible to false for Conan packages (#21275)

Fixes #21250
Related #20414

Conan packages don't have to follow SemVer.
The migration fixes the setting for all existing Conan and Generic
(#20414) packages.

models/migrations/v226.go

@@ -0,0 +1,15 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package migrations
+
+import (
+	"xorm.io/builder"
+	"xorm.io/xorm"
+)
+
+func fixPackageSemverField(x *xorm.Engine) error {
+	_, err := x.Exec(builder.Update(builder.Eq{"semver_compatible": false}).From("`package`").Where(builder.In("`type`", "conan", "generic")))
+	return err
+}