app version to server (#7130)

- Send app version and release stage to collab on connect
- Read the new header on the server

Release Notes:

- Added the ability to collaborate with users on different releases of
Zed.

crates/collab/Cargo.toml

@@ -61,6 +61,7 @@ util = { path = "../util" }
 uuid.workspace = true
 
 [dev-dependencies]
+release_channel = { path = "../release_channel" }
 async-trait.workspace = true
 audio = { path = "../audio" }
 call = { path = "../call", features = ["test-support"] }