2.21.2

Various fixes & improvements

• fix(rn): Remove hermesc envs if hermes is disabled (#1754) by @krystofwoldrich
• fix: Don't fail on duplicate proguard release association (#1762) by @loewenheim
• fix: Make URL in org auth tokens optional (#1766) by @loewenheim
• Explain how to update in the README (#1767) by @philipphofmann