Update GitHub Actions configs

Author: mattrubin

.github/workflows/carthage.yml

@@ -9,9 +9,9 @@ jobs:
     strategy:
       matrix:
         env:
-          - xcode: 13.4
+          - xcode: 15.4
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with:
           submodules: recursive
       - name: "Upgrade Carthage"

.github/workflows/spm.yml

@@ -9,9 +9,9 @@ jobs:
     strategy:
       matrix:
         env:
-          - xcode: 13.4
+          - xcode: 15.4
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: "Select Xcode ${{ matrix.env.xcode }}"
         uses: ./.github/actions/xcode-select
         with:

.github/workflows/xcode.yml

@@ -9,17 +9,17 @@ jobs:
     strategy:
       matrix:
         env:
-          - xcode: 13.4
+          - xcode: 15.4
             runtime: "iOS 15.5"
             device: "iPhone 13 Pro"
-          - xcode: 13.4
+          - xcode: 15.4
             runtime: "iOS 14.5"
             device: "iPhone 12 Pro Max"
-          - xcode: 13.4
+          - xcode: 15.4
             runtime: "iOS 13.7"
             device: "iPhone 11"
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with:
           submodules: recursive
       - name: "Select Xcode ${{ matrix.env.xcode }}"
@@ -54,17 +54,17 @@ jobs:
     strategy:
       matrix:
         env:
-          - xcode: 13.4
+          - xcode: 15.4
             runtime: "watchOS 8.5"
             device: "Apple Watch Series 7 - 45mm"
-          - xcode: 13.4
+          - xcode: 15.4
             runtime: "watchOS 7.4"
             device: "Apple Watch Series 6 - 44mm"
-          - xcode: 13.4
+          - xcode: 15.4
             runtime: "watchOS 6.2"
             device: "Apple Watch Series 4 - 40mm"
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with:
           submodules: recursive
       - name: "Select Xcode ${{ matrix.env.xcode }}"