move to slack links to CNCF slack

Signed-off-by: Terence Lee <[email protected]>

Author: hone

.github/ISSUE_TEMPLATE/config.yml

@@ -1,5 +1,5 @@
 blank_issues_enabled: true
 contact_links:
   - name: Community Slack
-    url: https://slack.buildpacks.io/
+    url: https://slack.cncf.io
     about: Chat with the community about any issues, questions, or feedback

README.md

@@ -11,7 +11,7 @@
 
 ### Calendar
 
-The calendar is managed via [teamup](https://teamup.com/ksxw26c3km72mq3imn). To request an alteration you may [create an issue](https://github.com/buildpacks/community/issues/new), reach out to a maintainer via [slack](https://slack.buildpacks.io), post in [discussions](https://github.com/buildpacks/community/discussions).
+The calendar is managed via [teamup](https://teamup.com/ksxw26c3km72mq3imn). To request an alteration you may [create an issue](https://github.com/buildpacks/community/issues/new), reach out to a maintainer via [slack](https://slack.cncf.io), post in [discussions](https://github.com/buildpacks/community/discussions).
 
 ## Contributing
 

config.toml

@@ -13,7 +13,7 @@ unsafe= true
 [params]
 twitter_handle = "buildpacks_io"
 github_base_url = "https://github.com/buildpacks"
-slack_invite_url = "https://slack.buildpacks.io/"
+slack_invite_url = "https://slack.cncf.io"
 description = "Cloud Native Buildpacks transform your application source code into images that can run on any cloud."
 
 pack_version_env_var = "PACK_VERSION"
@@ -66,7 +66,7 @@ pack_version_env_var = "PACK_VERSION"
 
   [[menu.footer2]]
   name       = "Slack"
-  url        = "https://slack.buildpacks.io/"
+  url        = "https://slack.cncf.io"
   weight     = 2
 
   [[menu.footer2]]