Update CI

.github/workflows/ci.yml

@@ -18,21 +18,21 @@ jobs:
     runs-on: macOS-latest
     steps:
     - name: Checkout
-      uses: actions/checkout@v2
+      uses: actions/checkout@v4
     - name: Build
       run: swift build
 
   linux:
     strategy:
       matrix:
         os: [ubuntu-latest]
-        swift: ["swift:5.4", "swift:5.5", "swift:5.6"]
+        swift: ["swift:5.9", "swift:5.10", "swift:6.0"]
     runs-on: ${{ matrix.os }}
     container:
       image: ${{ matrix.swift }}
     steps:
     - name: Checkout
-      uses: actions/checkout@v1
+      uses: actions/checkout@v4
       with:
         fetch-depth: 1
     - name: Build