Block publishing of zed_extension_api v0.0.7 (#12784)

This PR adds a temporary block on publishing v0.0.7 of the
`zed_extension_api`.

We have breaking changes to the extension API that are currently staged
on `main` and are still being iterated on, so we don't want to publish
again until we're ready to commit to the new API.

This change is intended to prevent accidental publishing of the crate
before we're ready.

Release Notes:

- N/A

crates/extension_api/Cargo.toml

@@ -8,6 +8,10 @@ keywords = ["zed", "extension"]
 edition = "2021"
 license = "Apache-2.0"
 
+# Don't publish v0.0.7 until we're ready to commit to the breaking API changes
+# Marshall is DRI on this.
+publish = false
+
 [lints]
 workspace = true