Update build to Xcode 26 / macOS 26 runner

.github/workflows/build_trio.yml

@@ -165,7 +165,7 @@ jobs:
   build:
     name: Build
     needs: [check_certs, check_status]
-    runs-on: macos-15
+    runs-on: macos-26
     permissions:
       contents: write
     if:
@@ -175,7 +175,7 @@ jobs:
         (vars.SCHEDULED_SYNC != 'false' && needs.check_status.outputs.NEW_COMMITS == 'true' )
     steps:
       - name: Select Xcode version
-        run: "sudo xcode-select --switch /Applications/Xcode_16.4.app/Contents/Developer"
+        run: "sudo xcode-select --switch /Applications/Xcode_26.2.app/Contents/Developer"
       
       - name: Checkout Repo for building
         uses: actions/checkout@v4

.github/workflows/unit_tests.yml

@@ -23,12 +23,12 @@ on:
 jobs:
   test:
     name: Run Unit Tests
-    runs-on: macos-15
+    runs-on: macos-26
     if: github.repository_owner == 'nightscout'
 
     steps:
       - name: Select Xcode version
-        run: sudo xcode-select -s /Applications/Xcode_16.4.app/Contents/Developer
+        run: sudo xcode-select -s /Applications/Xcode_26.2.app/Contents/Developer
 
       - name: Checkout code
         uses: actions/checkout@v4