fix broken links (onnx#4108)

Signed-off-by: Chun-Wei Chen <[email protected]>

Co-authored-by: Prasanth Pulavarthi <[email protected]>

CODEOWNERS

@@ -1,5 +1,5 @@
 * @onnx/sig-archinfra-approvers
-/community  @onnx/steering-commmittee
+/community  @onnx/steering-committee
 /onnx/defs  @onnx/sig-operators-approvers
 /onnx/backend/test  @onnx/sig-operators-approvers
 /docs/AddNewOp.md @onnx/sig-operators-approvers

README.md

@@ -41,7 +41,7 @@ If you think some operator should be added to ONNX specification, please read
 [this document](docs/AddNewOp.md).
 
 # Discuss
-We encourage you to open [Issues](https://github.com/onnx/onnx/issues), or use [Slack](https://slack.lfai.foundation/) for more real-time discussion
+We encourage you to open [Issues](https://github.com/onnx/onnx/issues), or use [Slack](https://lfaifoundation.slack.com/) (If you have not joined yet, please use this [link](https://join.slack.com/t/lfaifoundation/shared_invite/zt-o65errpw-gMTbwNr7FnNbVXNVFkmyNA) to join the group) for more real-time discussion.
 
 # Follow Us
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