gossipsub: Add table to track implementation status

of Gossipsub versions and extensions.

Author: MarcoPolo

pubsub/gossipsub/implementation-status.md

@@ -0,0 +1,34 @@
+# Implementation status of Gossipsub versions and Extensions
+
+This doc is meant to provide an overview of the implementation status of
+Gossipsub versions and Extensions.
+
+## Gossipsub Versions
+
+|               | [1.2] | [1.3-alpha]                                                    |
+| ------------- | ----- | -------------------------------------------------------------- |
+| [Go libp2p]   | ✅    | [Open PR](https://github.com/libp2p/go-libp2p-pubsub/pull/630) |
+| [Rust libp2p] | ✅    | In Progress                                                    |
+| [JS libp2p]   | ✅    | Not started                                                    |
+| [Nim libp2p]  | ✅    | Not started                                                    |
+| [Java libp2p] | ✅    | Not started                                                    |
+
+## Gossipsub Extensions
+
+|               | [Choke Extensions] | [Partial Messages] |
+| ------------- | ------------------ | ------------------ |
+| [Go libp2p]   | Not Implemented    | PR Soon            |
+| [Rust libp2p] | Not Implemented    | Not Implemented    |
+| [JS libp2p]   | Not Implemented    | Not Implemented    |
+| [Nim libp2p]  | Not Implemented    | Not Implemented    |
+| [Java libp2p] | Not Implemented    | Not Implemented    |
+
+[Go libp2p]: https://github.com/libp2p/go-libp2p-pubsub
+[Rust libp2p]: https://github.com/libp2p/rust-libp2p/tree/master/protocols/gossipsub
+[JS libp2p]: https://github.com/ChainSafe/js-libp2p-gossipsub
+[Nim libp2p]: https://github.com/vacp2p/nim-libp2p/tree/master/libp2p/protocols/pubsub/gossipsub
+[Java libp2p]: https://github.com/libp2p/jvm-libp2p/tree/develop/libp2p/src/test/kotlin/io/libp2p/pubsub/gossip
+[1.2]: https://github.com/libp2p/specs/blob/master/pubsub/gossipsub/gossipsub-v1.2.md
+[1.3-alpha]: https://github.com/libp2p/specs/issues/687
+[Choke Extensions]: https://github.com/libp2p/specs/pull/681
+[Partial Messages]: https://github.com/libp2p/specs/pull/685