try latest os version for unit tests to avoid random failures

Author: harsh62

.github/workflows/unit_tests.yml

@@ -8,11 +8,11 @@ on:
 
 jobs:
   unit-test-ios:
-    runs-on: macos-latest
+    runs-on: macos-15
     steps:
       - uses: actions/checkout@8e5e7e5ab8b370d6c329ec480221332ada57f0ab # v3.5.2
       - name: Unit test Authenticator on iOS
-        run: xcodebuild test -scheme Authenticator -sdk 'iphonesimulator' -destination 'platform=iOS Simulator,name=iPhone 14,OS=latest' -derivedDataPath Build/ -enableCodeCoverage YES -clonedSourcePackagesDirPath ~/Library/Developer/Xcode/DerivedData/Authenticator | xcpretty --simple --color --report junit && exit ${PIPESTATUS[0]}
+        run: xcodebuild test -scheme Authenticator -sdk 'iphonesimulator' -destination 'platform=iOS Simulator,name=iPhone 16,OS=latest' -derivedDataPath Build/ -enableCodeCoverage YES -clonedSourcePackagesDirPath ~/Library/Developer/Xcode/DerivedData/Authenticator | xcpretty --simple --color --report junit && exit ${PIPESTATUS[0]}
       - name: Generate Coverage Report
         continue-on-error: true
         run: |