Change RpcClient methods to take shared references

This will make it easier to spawn a future on gpui's executors
when calling `RpcClient` methods.

Co-Authored-By: Max Brunsfeld <max@zed.dev>

Cargo.lock

@@ -1350,6 +1350,7 @@ checksum = "da9052a1a50244d8d5aa9bf55cbc2fb6f357c86cc52e46c62ed390a7180cf150"
 dependencies = [
  "futures-channel",
  "futures-core",
+ "futures-executor",
  "futures-io",
  "futures-sink",
  "futures-task",
@@ -1372,6 +1373,17 @@ version = "0.3.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "79e5145dde8da7d1b3892dad07a9c98fc04bc39892b1ecc9692cf53e2b780a65"
 
+[[package]]
+name = "futures-executor"
+version = "0.3.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e9e59fdc009a4b3096bf94f740a0f2424c082521f20a9b08c5c07c48d90fd9b9"
+dependencies = [
+ "futures-core",
+ "futures-task",
+ "futures-util",
+]
+
 [[package]]
 name = "futures-io"
 version = "0.3.12"
@@ -1423,6 +1435,7 @@ version = "0.3.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "632a8cd0f2a4b3fdea1657f08bde063848c3bd00f9bbf6e256b8be78802e624b"
 dependencies = [
+ "futures-channel",
  "futures-core",
  "futures-io",
  "futures-macro",
@@ -4304,7 +4317,7 @@ dependencies = [
  "easy-parallel",
  "env_logger",
  "fsevent",
- "futures-core",
+ "futures",
  "gpui",
  "http-auth-basic",
  "ignore",