feat: update version references in any files

updater.go

@@ -1,12 +1,36 @@
 package rp
 
 import (
-	"context"
-
-	"github.com/go-git/go-git/v5"
+	"regexp"
+	"strings"
 )
 
-func RunUpdater(ctx context.Context, version string, worktree *git.Worktree) error {
-	// TODO: Implement updater for Go,Python,ExtraFilesMarkers
-	return nil
+const (
+	InlineUpdateMarker = "x-releaser-pleaser-version"
+)
+
+var (
+	SemVerRegex = regexp.MustCompile(`(?<major>\d+)\.(?<minor>\d+)\.(?<patch>\d+)(-(?<preRelease>[\w.]+))?(\+(?<build>[-\w.]+))?`)
+)
+
+type Updater interface {
+	UpdateContent(content, version string) string
+}
+
+type GenericUpdater struct{}
+
+func (u *GenericUpdater) UpdateContent(content, version string) string {
+	// TODO: use buffered input/output
+	output := strings.Builder{}
+	output.Grow(len(content))
+	for _, line := range strings.Split(content, "\n") {
+		if strings.Contains(line, InlineUpdateMarker) {
+			line = SemVerRegex.ReplaceAllLiteralString(line, version)
+		}
+
+		output.WriteString(line)
+		output.WriteByte('\n')
+	}
+
+	return output.String()
 }