update CI actions

Author: CamJN

.github/workflows/swift.yml

@@ -15,7 +15,7 @@ jobs:
     permissions:
       contents: write
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v5
       with:
         repository: getargv/getargv
         path: getargv
@@ -26,7 +26,7 @@ jobs:
     - name: Install libgetargv
       run: sudo make install_dylib
       working-directory: getargv
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v5
       with:
         path: getargv-swift
         fetch-tags: true