Fix TAG Security charter link in Contributing (#1465)

Fixes #1460

Author: aerabi

CONTRIBUTING.md

@@ -140,7 +140,7 @@ following guidelines.
 ### Guidelines
 
 - Presentations are encouraged to expose the TAG to cloud native open source projects, cloud native security concepts, and other cloud native or security groups.
-- Presentations should fit with [our charter](https://github.com/cncf/tag-security/blob/main/governance/charter.md)
+- Presentations should fit with [our charter](https://github.com/cncf/toc/blob/main/tags/tag-charters/security-charter.md)
 - Presentations should not be scheduled on the Agenda until the issue is filled in and the TAG representative has performed due diligence on the issue
 - Presentations should abide by the CNCF code of conduct