ci: pin Xcode version for CocoaPods publish jobs (#758)

* ci: pin Xcode version for CocoaPods publish jobs

CocoaPods publish jobs ran on the macos-15 runner's default Xcode,
which lacks the iOS 26 SDK. Dependencies like Airship use
#available(iOS 26.0, *) guards — Swift still type-checks these blocks
even on older toolchains, causing compile errors that don't reproduce
locally on Xcode 26.2.

Both publish jobs now select Xcode explicitly. The kit job reads
xcode_version from the matrix entry (e.g. Braze uses 16.4), falling
back to 26.2 when unset.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* ci: use macos-latest for CocoaPods publish jobs

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: nickolas-dimitrakas

.github/workflows/release-publish.yml

@@ -312,12 +312,17 @@ jobs:
   publish-core-cocoapods:
     name: Publish Core SDK to CocoaPods
     needs: [mirror-and-release-kits]
-    runs-on: macos-15
+    runs-on: macos-latest
     if: github.event.inputs.dry_run != 'true'
+    env:
+      XCODE_VERSION: "26.2"
     steps:
       - name: Checkout code
         uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
 
+      - name: Select Xcode
+        run: sudo xcode-select -s /Applications/Xcode_${{ env.XCODE_VERSION }}.app
+
       - name: Publish core podspecs
         env:
           COCOAPODS_TRUNK_TOKEN: ${{ secrets.COCOAPODS_TRUNK_TOKEN }}
@@ -332,8 +337,10 @@ jobs:
   publish-kit-cocoapods:
     name: Publish ${{ matrix.kit.name }} to CocoaPods
     needs: [load-matrix, publish-core-cocoapods]
-    runs-on: macos-15
+    runs-on: macos-latest
     if: github.event.inputs.dry_run != 'true'
+    env:
+      XCODE_VERSION: ${{ matrix.kit.xcode_version || '26.2' }}
     strategy:
       fail-fast: false
       matrix:
@@ -342,6 +349,9 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
 
+      - name: Select Xcode
+        run: sudo xcode-select -s /Applications/Xcode_${{ env.XCODE_VERSION }}.app
+
       - name: Wait for core SDK on CocoaPods CDN
         run: |
           VERSION=$(head -n 1 VERSION | tr -d '\r\n ')