update src folder links (#199)

src/ExitCode.php

@@ -7,7 +7,7 @@
 /**
  * This class provides constants for defining console command exit codes.
  *
- * The exit codes follow the codes defined in the [FreeBSD sysexits(3)](http://man.openbsd.org/sysexits) manual page.
+ * The exit codes follow the codes defined in the [FreeBSD sysexits(3)](https://man.openbsd.org/sysexits) manual page.
  *
  * These constants can be used in console controllers for example like this:
  *