docs: remove slack (#8565)

Author: itaysk

README.md

@@ -116,7 +116,6 @@ If you'd like to contact Aqua or request a demo, please use this form: <https://
 Trivy is an [Aqua Security][aquasec] open source project.  
 Learn about our open source work and portfolio [here][oss].  
 Contact us about any matter by opening a GitHub Discussion [here][discussions]
-Join our [Slack community][slack] to stay up to date with community efforts.
 
 Please ensure to abide by our [Code of Conduct][code-of-conduct] during all interactions.
 
@@ -133,7 +132,6 @@ Please ensure to abide by our [Code of Conduct][code-of-conduct] during all inte
 [homepage]: https://trivy.dev
 [docs]: https://trivy.dev/latest/docs/
 [pronunciation]: #how-to-pronounce-the-name-trivy
-[slack]: https://slack.aquasec.com
 [code-of-conduct]: https://github.com/aquasecurity/community/blob/main/CODE_OF_CONDUCT.md
 
 [Installation]:https://trivy.dev/latest/getting-started/installation/

mkdocs.yml

@@ -274,8 +274,6 @@ extra:
       link: https://twitter.com/AquaTrivy
     - icon: fontawesome/brands/github
       link: https://github.com/aquasecurity/trivy
-    - icon: fontawesome/brands/slack
-      link: https://github.com/aquasecurity/trivy
   analytics:
     provider: google
     property: G-V9LJGFH7GX