Update image sig dates for q4 (#127)

* Updated the next Image SIG date to Dec 14, 2023.

* Updated the Image SIG previous and upcoming meetings.

* Added the Image SIG presentation from Sep 21, 2023

Author: melonakos

README.rst

@@ -88,7 +88,7 @@ Upcoming oneAPI Community Forum Meetings
      - Math SIG
      - Virtual
      - Contact_
-   * - 21 September 2023, 10am-11am US Central Time
+   * - 14 December 2023, 10am-11am US Central Time
      - Image SIG
      - Virtual
      - Contact_

image/README.rst

@@ -95,13 +95,16 @@ The Image SIG is led by John Melonakos.
 Upcoming Meetings
 =================
 
+The next Image SIG will be held on December 14, 2023, from 10am to 11am CST.
+
 To join the Image SIG, email oneapi@codeplay.com to register for our quarterly
 meetings. You will be added to the mailing list and notified of upcoming
 events.
 
 Previous Meetings
 =================
 
+| September 21, 2023 - `presentation <presentations/2023-09-21_Slides.pdf>`__
 | June 21, 2023 - `presentation <presentations/2023-06-21_Slides.pdf>`__
 | February 17, 2022 - `notes <minutes/2022_02_17_Minutes.rst>`__, \
  `presentation <presentations/2022-02-17_Slides.pdf>`__