Upgrade rust/crates/futures-channel to 0.3.7

Test: make all rust crates
Change-Id: Ibf0e97bc81bcbc975ec0c85865ab19f2ef3d8652
diff --git a/Cargo.toml b/Cargo.toml
index 5a3f79d..e5feaad 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -13,21 +13,22 @@
 [package]
 edition = "2018"
 name = "futures-channel"
-version = "0.3.5"
+version = "0.3.7"
 authors = ["Alex Crichton <alex@alexcrichton.com>"]
 description = "Channels for asynchronous communication using futures-rs.\n"
 homepage = "https://rust-lang.github.io/futures-rs"
-documentation = "https://docs.rs/futures-channel/0.3.5"
+documentation = "https://docs.rs/futures-channel/0.3.7"
 license = "MIT OR Apache-2.0"
 repository = "https://github.com/rust-lang/futures-rs"
 [package.metadata.docs.rs]
 all-features = true
+rustdoc-args = ["--cfg", "docsrs"]
 [dependencies.futures-core]
-version = "0.3.5"
+version = "0.3.7"
 default-features = false
 
 [dependencies.futures-sink]
-version = "0.3.5"
+version = "0.3.7"
 optional = true
 default-features = false