docs: add Kubernetes version support list (#2661)

Signed-off-by: Daniel Weiße <dw@edgeless.systems>

hack/versioninfogen/main.go

@@ -0,0 +1,74 @@
+/*
+Copyright (c) Edgeless Systems GmbH
+
+SPDX-License-Identifier: AGPL-3.0-only
+*/
+
+package main
+
+import (
+	"flag"
+	"fmt"
+	"io"
+	"os"
+	"strings"
+
+	"github.com/edgelesssys/constellation/v2/internal/semver"
+	"github.com/edgelesssys/constellation/v2/internal/versions"
+)
+
+const fileSeparator = "<!--AUTO_GENERATED_BY_BAZEL-->\n<!--DO_NOT_EDIT-->\n"
+
+func main() {
+	filePath := flag.String("file-path", "../../docs/docs/architecture/versions.md", "path to the version file to update")
+	flag.Parse()
+
+	k8sVersionStrings := versions.SupportedK8sVersions()
+	var k8sVersions []semver.Semver
+	for _, k8sVersionString := range k8sVersionStrings {
+		k8sVersion, err := semver.New(k8sVersionString)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "invalid kubernetes version %q: %s", k8sVersionString, err)
+			os.Exit(1)
+		}
+		k8sVersions = append(k8sVersions, k8sVersion)
+	}
+
+	if err := updateDocFile(*filePath, k8sVersions); err != nil {
+		fmt.Fprintf(os.Stderr, "error updating versions file: %s\n", err)
+		os.Exit(1)
+	}
+}
+
+func updateDocFile(filePath string, supportedVersions []semver.Semver) error {
+	fileHeader, err := readVersionsFile(filePath)
+	if err != nil {
+		return err
+	}
+
+	var versionList strings.Builder
+	for _, version := range supportedVersions {
+		if _, err := versionList.WriteString(
+			fmt.Sprintf("* %s\n", version.String()),
+		); err != nil {
+			return fmt.Errorf("writing matrix doc file: %w", err)
+		}
+	}
+
+	return os.WriteFile(filePath, []byte(fileHeader+fileSeparator+versionList.String()), 0o644)
+}
+
+func readVersionsFile(filePath string) (string, error) {
+	f, err := os.Open(filePath)
+	if err != nil {
+		return "", fmt.Errorf("opening version info file: %w", err)
+	}
+	defer f.Close()
+
+	fileContentRaw, err := io.ReadAll(f)
+	if err != nil {
+		return "", fmt.Errorf("reading version info file: %w", err)
+	}
+	fileContent := strings.Split(string(fileContentRaw), fileSeparator)
+	return fileContent[0], nil
+}