message: Fix binstall support: Specify that only x86_64 linux gnu is supported
diff: @@ -63,7 +63,7 @@ rustc_version = "0.4"
  [dev-dependencies]
  rusty-fork = "0.3.0"
  -[package.metadata.binstall]
  +[package.metadata.binstall."x86_64-unknown-linux-gnu"]
  pkg-url = "{ repo }/releases/download/{ version }/cargo-tarpaulin-{ version }-travis.tar.gz"
  bin-dir = "cargo-tarpaulin"
  pkg-fmt = "tgz"
  