Use Xcode 14.3 and CocoaPods 1.12.1

This was done to address the following CI failure when building with the
Gutenberg XCFramework:

```
▸ Linking WordPress
⚠️  ld: Could not find or use auto-linked library 'swiftCompatibility56'

❌  ld: symbol(s) not found for architecture x86_64
```

https://buildkite.com/automattic/wordpress-ios/builds/14356#01885545-c05a-43a8-b475-d0d683857672

The CocoaPods upgrade was necessary to work around an incompatibility
issue with the earlier CP version and Xcode 14.3 when archiving.

.buildkite/cache-builder.yml

@@ -14,7 +14,7 @@ common_params:
   # Common environment values to use with the `env` key.
   - &common_env
     # Be sure to also update the `.xcode-version` file when updating the Xcode image/version here
-    IMAGE_ID: xcode-14.2
+    IMAGE_ID: xcode-14.3
 
 steps:
 

.buildkite/pipeline.yml

@@ -9,7 +9,7 @@ common_params:
   # Common environment values to use with the `env` key.
   - &common_env
     # Be sure to also update the `.xcode-version` file when updating the Xcode image/version here
-    IMAGE_ID: xcode-14.2
+    IMAGE_ID: xcode-14.3
 
 # This is the default pipeline – it will build and test the app
 steps:

.buildkite/release-builds.yml

@@ -11,7 +11,7 @@ common_params:
   # Common environment values to use with the `env` key.
   - &common_env
     # Be sure to also update the `.xcode-version` file when updating the Xcode image/version here
-    IMAGE_ID: xcode-14.2
+    IMAGE_ID: xcode-14.3
 
 steps:
 

Gemfile

@@ -3,7 +3,7 @@
 source 'https://rubygems.org'
 
 gem 'archive-tar-minitar'
-gem 'cocoapods', '~> 1.11'
+gem 'cocoapods', '~> 1.12', '>= 1.12.1'
 gem 'commonmarker'
 gem 'danger', '~> 9.3'
 gem 'danger-rubocop', '~> 0.10'

Gemfile.lock

@@ -381,7 +381,7 @@ PLATFORMS
 
 DEPENDENCIES
   archive-tar-minitar
-  cocoapods (~> 1.11)
+  cocoapods (~> 1.12, >= 1.12.1)
   commonmarker
   danger (~> 9.3)
   danger-rubocop (~> 0.10)