Extract GitHub token from file if --github-token or env variable GITHUB_TOKEN is not present (#849)

- Add option `--no-discover-github-token` for disabling this behavior
 - Add new dep gh-token v0.1.0 to crates/bin
 - Extract github-token from git-credentials or gh config if `--github-token` or
    environment variable `GITHUB_TOKEN` is not present.

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

Cargo.lock

@@ -346,6 +346,7 @@ dependencies = [
  "embed-resource",
  "file-format",
  "fs-lock",
+ "gh-token",
  "log",
  "miette",
  "mimalloc",
@@ -803,6 +804,18 @@ dependencies = [
  "wasi",
 ]
 
+[[package]]
+name = "gh-token"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bc623f67e9004eac91ad251d7d4c0b1fa7ac53646c09d9c8ef6e27a21b2d02fd"
+dependencies = [
+ "home",
+ "serde",
+ "serde_derive",
+ "serde_yaml",
+]
+
 [[package]]
 name = "gimli"
 version = "0.27.2"
@@ -1964,6 +1977,19 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "serde_yaml"
+version = "0.9.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8fb06d4b6cdaef0e0c51fa881acb721bed3c924cfaa71d9c94a3b771dfdf6567"
+dependencies = [
+ "indexmap",
+ "itoa",
+ "ryu",
+ "serde",
+ "unsafe-libyaml",
+]
+
 [[package]]
 name = "sharded-slab"
 version = "0.1.4"
@@ -2541,6 +2567,12 @@ version = "0.1.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c0edd1e5b14653f783770bce4a4dabb4a5108a5370a5f5d8cfe8710c361f6c8b"
 
+[[package]]
+name = "unsafe-libyaml"
+version = "0.2.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bc7ed8ba44ca06be78ea1ad2c3682a43349126c8818054231ee6f4748012aed2"
+
 [[package]]
 name = "untrusted"
 version = "0.7.1"