Use the new syntax for Markdown admonitions

Author: Widcket

CONTRIBUTING.md

@@ -1,6 +1,6 @@
 # Contributing
 
-> **Note**
+> [!IMPORTANT]
 > Tests must be added for all new functionality. Existing tests must be updated for all changed/fixed functionality, where applicable. All tests must complete without errors. All new functionality must be documented as well.
 
 ## Environment setup

EXAMPLES.md

@@ -34,7 +34,7 @@ When creating the SimpleKeychain instance, specify the access group that the app
 let simpleKeychain = SimpleKeychain(accessGroup: "ABCDEFGH.com.example.myaccessgroup")
 ```
 
-> **Note**
+> [!NOTE]
 > For more information on access group sharing, see [Sharing Access to Keychain Items Among a Collection of Apps](https://developer.apple.com/documentation/security/keychain_services/keychain_items/sharing_access_to_keychain_items_among_a_collection_of_apps).
 
 ## Share items with other devices through iCloud synchronization
@@ -45,7 +45,7 @@ When creating the SimpleKeychain instance, set `synchronizable` to `true` to ena
 let simpleKeychain = SimpleKeychain(sychronizable: true)
 ```
 
-> **Note**
+> [!NOTE]
 > For more information on iCloud synchronization, check the [kSecAttrSynchronizable documentation](https://developer.apple.com/documentation/security/ksecattrsynchronizable).
 
 ## Restrict item accessibility based on device state
@@ -56,7 +56,7 @@ When creating the SimpleKeychain instance, specify a custom accesibility value t
 let simpleKeychain = SimpleKeychain(accessibility: .whenUnlocked)
 ```
 
-> **Note**
+> [!NOTE]
 > For more information on accessibility, see [Restricting Keychain Item Accessibility](https://developer.apple.com/documentation/security/keychain_services/keychain_items/restricting_keychain_item_accessibility).
 
 ## Require Touch ID / Face ID to retrieve an item
@@ -70,7 +70,7 @@ let simpleKeychain = SimpleKeychain(accessControlFlags: .biometryCurrentSet,
                                     context: context)
 ```
 
-> **Note**
+> [!NOTE]
 > For more information on access control, see [Restricting Keychain Item Accessibility](https://developer.apple.com/documentation/security/keychain_services/keychain_items/restricting_keychain_item_accessibility).
 
 ---

README.md

@@ -26,7 +26,7 @@ Migrating from 0.x? Check the [Migration Guide](V1_MIGRATION_GUIDE.md).
 - Xcode 13.x / 14.x
 - Swift 5.x
 
-> **Note**
+> [!IMPORTANT]
 > Check the [Support Policy](#support-policy) to learn when dropping Xcode, Swift, and platform versions will not be considered a **breaking change**.
 
 ### Installation