cache --cleanup should handle directories created by restic check.

Because there is no guarantee that a cleanup of these directories will occur
after the "restic check", we extend the behavior to detect and manage these
specific cache directories and allow their cleanup too.

internal/cache/cache.go

@@ -172,7 +172,7 @@ func updateTimestamp(d string) error {
 const MaxCacheAge = 30 * 24 * time.Hour
 
 func validCacheDirName(s string) bool {
-	r := regexp.MustCompile(`^[a-fA-F0-9]{64}$`)
+	r := regexp.MustCompile(`^[a-fA-F0-9]{64}$|^restic-check-cache-[0-9]+$`)
 	return r.MatchString(s)
 }