Update to v2 of Contributor Covenant in shared GitHub repo (#15)

Author: j-f1

CODE_OF_CONDUCT.md

@@ -1,2 +1,9 @@
 # blog.swiftwasm.org
 SwiftWasm organization blog
+
+### Code of Conduct
+
+This project adheres to the [Contributor Covenant Code of
+Conduct](https://github.com/swiftwasm/.github/blob/main/CODE_OF_CONDUCT.md).
+By participating, you are expected to uphold this code. Please report
+unacceptable behavior to hello@swiftwasm.org.