removed IRC link as generally unattended and updated Slack invite link
This closes
@@ -296,9 +296,7 @@ If you have questions, you can reach out to our mailing list: dev@nifi.apache.or
- Apache NiFi Slack Workspace: https://apachenifi.slack.com/
- New users can join the workspace using the following [invite link](https://s.apache.org/nifi-community-slack).
-
-- IRC: #nifi on [irc.freenode.net](https://webchat.freenode.net/?channels=#nifi)
+ New users can join the workspace using the following [invite link](https://join.slack.com/t/apachenifi/shared_invite/zt-11njbtkdx-ZRU8FKYSWoEHRJetidy0zA).
To submit a feature request or bug report, please file a Jira at [https://issues.apache.org/jira/projects/NIFI/issues](https://issues.apache.org/jira/projects/NIFI/issues). If this is a **security vulnerability report**, please email [security@nifi.apache.org](mailto:security@nifi.apache.org) directly and review the [Apache NiFi Security Vulnerability Disclosure](https://nifi.apache.org/security.html) and [Apache Software Foundation Security](https://www.apache.org/security/committers.html) processes first.
