Added link to slack channel on k8s workspace #2279

Job	Run time
Rustfmt	19s
Check	9m 58s
Test Suite	14m 17s
Bench	24m 58s
Clippy	12m 58s
Try in kind (Kubernetes in Docker)	1m 31s
Build for WASM	55s
	1h 4m 56s

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