Update Xcode image to 14.2 and increase release build priority

Author: spencertransier

.buildkite/pipeline.yml

@@ -5,7 +5,7 @@ common_params:
     - automattic/bash-cache#2.9.0
   # Common environment values to use with the `env` key.
   - &common_env
-    IMAGE_ID: xcode-14.0.1
+    IMAGE_ID: xcode-14.2
 
 # This is the default pipeline – it will build and test the app
 steps:

.buildkite/release-build.yml

@@ -5,11 +5,12 @@ common_params:
     - automattic/bash-cache#2.9.0
   # Common environment values to use with the `env` key.
   - &common_env
-    IMAGE_ID: xcode-14.0.1
+    IMAGE_ID: xcode-14.2
 
 # This is the default pipeline – it will build and test the app
 steps:
   - label: "🛠 App Store Upload"
     command: .buildkite/commands/build-and-upload-release.sh
+    priority: 1
     env: *common_env
     plugins: *common_plugins