Adding 12.18.24 OSCAL Implementers Slide Deck (#139)

* Add files via upload

* Update _index.md

Adding the link to the December 18, 2024 Implementers slide deck

Author: jjahearn22

content/collaborate/meetings/implementers/_index.md

@@ -21,6 +21,7 @@ Participants can find meeting information by [subscribing to the mailing list](h
 
 Below is a list of presentations from past Data Bytes meetings.
 
+- [Meeting Slides from December 18, 2024](/pdf/oscal_implementers_20241218.pdf)
 - [Meeting Slides from December 4, 2024](/pdf/oscal_implementers_20241204.pdf)
 - [Meeting Slides from November 13, 2024](/pdf/oscal_implementers_20241113.pdf)
 - [Meeting Slides from October 30, 2024](/pdf/oscal_implementers_20241030.pdf)