ci: upgrade actions

Author: chaoticlonghair

.github/workflows/ci.yaml

@@ -16,7 +16,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout the Repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Install Rust Toolchain
         run: |
           rustup toolchain install ${{ env.RUST_TOOLCHAIN }} --profile minimal --component rustfmt
@@ -28,7 +28,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout the Repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Install Rust Toolchain
         run: |
           rustup toolchain install ${{ env.RUST_TOOLCHAIN }} --profile minimal --component clippy
@@ -46,7 +46,7 @@ jobs:
       max-parallel: 3
     steps:
       - name: Checkout the Repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           submodules: recursive
       - name: Install Rust Toolchain

README.md

@@ -1,13 +1,15 @@
 # CKB Bitcoin SPV
 
 [![License]](#license)
+[![GitHub Actions]](https://github.com/ckb-cell/ckb-bitcoin-spv/actions)
 
 > [!WARNING]
 > This repository is still in the proof-of-concept stage.
 
 A [Bitcoin] SPV library, which is used to develop Bitcoin SPV on [CKB].
 
 [License]: https://img.shields.io/badge/License-MIT-blue.svg
+[GitHub Actions]: https://github.com/ckb-cell/ckb-bitcoin-spv/workflows/CI/badge.svg
 
 ## Resources