config: Bump POSIX spec references to IEEE Std 1003.1-2008, 2016 Edition

These references had been using IEEE Std 1003.1, 2004 Edition, but:

  $ curl -s http://pubs.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap08.html | grep -B2 'newer edition'
  <center><font size="2">The Open Group Base Specifications Issue 6<br>
  IEEE Std 1003.1, 2004 Edition<br>
  Copyright &copy; 2001-2004 The IEEE and The Open Group, All Rights reserved.</font></center><center><font color="red">A newer edition of this document exists <a href="http://pubs.opengroup.org/onlinepubs/9699919799/" target="_parent">here</a></font></center>

Shifting to 2016 also syncs us with the 'file' reference in
config-linux.md.  The initial reasoning for the 2004 edition is
unclear to me (more on that in 70858bc, config: Adjust process.args
to cite POSIX's execvp, 2016-05-19, #427),

The change-log for the exec page [1] doesn't list any relevant
changes, and skimming a diff of the two HTML pages didn't turn up
anything significant.

Diffing the two HTML pages for environment variables also turned up no
significant changes.  Both definition reference the Portable Character
Set for uppercase letters, digits, and underscore, but the U####
values for those have not changed [2,3].

[1]: http://pubs.opengroup.org/onlinepubs/9699919799/functions/exec.html#tag_16_111_14
[2]: http://pubs.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap06.html#tag_06_01
[3]: http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap06.html#tag_06_01

Signed-off-by: W. Trevor King <[email protected]>

Author: wking

config.md

@@ -142,8 +142,8 @@ For all platform-specific configuration values, the scope defined below in the [
     * **`width`** (uint, REQUIRED)
 * **`cwd`** (string, REQUIRED) is the working directory that will be set for the executable.
     This value MUST be an absolute path.
-* **`env`** (array of strings, OPTIONAL) with the same semantics as [IEEE Std 1003.1-2001's `environ`][ieee-1003.1-2001-xbd-c8.1].
-* **`args`** (array of strings, REQUIRED) with similar semantics to [IEEE Std 1003.1-2001 `execvp`'s *argv*][ieee-1003.1-2001-xsh-exec].
+* **`env`** (array of strings, OPTIONAL) with the same semantics as [IEEE Std 1003.1-2008's `environ`][ieee-1003.1-2008-xbd-c8.1].
+* **`args`** (array of strings, REQUIRED) with similar semantics to [IEEE Std 1003.1-2008 `execvp`'s *argv*][ieee-1003.1-2008-xsh-exec].
     This specification extends the IEEE standard in that at least one entry is REQUIRED, and that entry is used with the same semantics as `execvp`'s *file*.
 * **`capabilities`** (object, OPTIONAL) is an object containing arrays that specifies the sets of capabilities for the process(es) inside the container.
     Valid values are platform-specific.
@@ -375,10 +375,10 @@ On Linux, they are run after the container namespaces are created.
 * **`hooks`** (object, OPTIONAL) MAY contain any of the following properties:
     * **`prestart`** (array of objects, OPTIONAL) is an array of [pre-start hooks](#prestart).
         Entries in the array contain the following properties:
-        * **`path`** (string, REQUIRED) with similar semantics to [IEEE Std 1003.1-2001 `execv`'s *path*][ieee-1003.1-2001-xsh-exec].
+        * **`path`** (string, REQUIRED) with similar semantics to [IEEE Std 1003.1-2008 `execv`'s *path*][ieee-1003.1-2008-functions-exec].
             This specification extends the IEEE standard in that **`path`** MUST be absolute.
-        * **`args`** (array of strings, OPTIONAL) with the same semantics as [IEEE Std 1003.1-2001 `execv`'s *argv*][ieee-1003.1-2001-xsh-exec].
-        * **`env`** (array of strings, OPTIONAL) with the same semantics as [IEEE Std 1003.1-2001's `environ`][ieee-1003.1-2001-xbd-c8.1].
+        * **`args`** (array of strings, OPTIONAL) with the same semantics as [IEEE Std 1003.1-2008 `execv`'s *argv*][ieee-1003.1-2008-functions-exec].
+        * **`env`** (array of strings, OPTIONAL) with the same semantics as [IEEE Std 1003.1-2008's `environ`][ieee-1003.1-2008-xbd-c8.1].
         * **`timeout`** (int, OPTIONAL) is the number of seconds before aborting the hook.
             If set, `timeout` MUST be greater than zero.
     * **`poststart`** (array of objects, OPTIONAL) is an array of [post-start hooks](#poststart).
@@ -854,8 +854,8 @@ Here is a full example `config.json` for reference.
 [procfs_2]: https://www.kernel.org/doc/Documentation/filesystems/proc.txt
 [semver-v2.0.0]: http://semver.org/spec/v2.0.0.html
 [go-environment]: https://golang.org/doc/install/source#environment
-[ieee-1003.1-2001-xbd-c8.1]: http://pubs.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap08.html#tag_08_01
-[ieee-1003.1-2001-xsh-exec]: http://pubs.opengroup.org/onlinepubs/009695399/functions/exec.html
+[ieee-1003.1-2008-xbd-c8.1]: http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap08.html#tag_08_01
+[ieee-1003.1-2008-xsh-exec]: http://pubs.opengroup.org/onlinepubs/9699919799/functions/exec.html
 [naming-a-volume]: https://aka.ms/nb3hqb
 
 [capabilities.7]: http://man7.org/linux/man-pages/man7/capabilities.7.html