Link to the slack community in the docs is outdated #38

[proppy]

Expected Behavior

Docs should point to https://open-source-silicon.dev/

Actual Behavior

Docs point to https://join.skywater.tools/

Steps to Reproduce the Problem

1. Go to https://skywater-pdk.readthedocs.io/en/main/
2. Click on the "🗨️ Chat" link in the top nav
3. See https://github.com/google/skywater-pdk/blob/60fe154d3b573493c78daae454949ff96547cafe/docs/_templates/relbar.html#L8

Specifications

• Version: latest
• Platform: all