Rm unnecessary warning msg "Failed to read git credential file" (#1479)

* Rm unnecessary warning msg "Failed to read git credential file"

Fixed #1476

If `gh auth token` executed successfully and binstall obtained a gh
token from it, then there's no reason to issue any warning msg.

Only when binstall cannot read from `.git-credential` and
`gh auth token` failed does binstall need to issue warning.

Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>

* Fix clippy warning

Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>

---------

Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>

crates/bin/src/gh_token.rs

@@ -1,9 +1,8 @@
 use std::{io, process};
 
 use compact_str::CompactString;
-use tracing::warn;
 
-fn get_inner() -> io::Result<CompactString> {
+pub(super) fn get() -> io::Result<CompactString> {
     let process::Output { status, stdout, .. } = process::Command::new("gh")
         .args(["auth", "token"])
         .stdin(process::Stdio::null())
@@ -26,13 +25,3 @@ fn get_inner() -> io::Result<CompactString> {
 
     Ok(s.trim().into())
 }
-
-pub(super) fn get() -> Option<CompactString> {
-    match get_inner() {
-        Ok(token) => Some(token),
-        Err(err) => {
-            warn!(?err, "Failed to retrieve token from `gh auth token`");
-            None
-        }
-    }
-}