docs: add jar documentation to zip file in a format fastlane can understand

plugins/fastlane-plugin-android_cd/README.md

@@ -22,7 +22,7 @@ To use these actions, you need to add some information to your Android folder so
 
 In your android folder, place a compressed folder containing:
 
-- The application's signing key (in the .jks format). If this is a new application, you can generate this key with the following command:
+* The application's signing key (in the .jks format). If this is a new application, you can generate this key with the following command:
 
 ```shel
 keytool -genkey -v -keystore key_store_name.keystore -alias key_alias_name -keyalg RSA -keysize 2048 -validity 10000
@@ -30,29 +30,39 @@ keytool -genkey -v -keystore key_store_name.keystore -alias key_alias_name -keya
 
 During the execution of the above command, you will be prompted to provide a password for your key. Make sure to remember this password, as you will need it later.
 
-- The key.properties file containing sensitive data for using the signing key, such as the path of the key or the password. If this file does not exist yet, create it and fill in the following fields:
+* The key.properties file containing sensitive data for using the signing key, such as the path of the key or the password. If this file does not exist yet, create it and fill in the following fields:
 
-  - `storeFile`: the relative or absolute path to the key storage file that contains the private key used to sign the Android application.
-  - `storePassword`: the password used to access the key storage file.
-  - `keyAlias`: the alias of the key used to sign the application.
-  - `keyPassword`: the password used to access the key.
+  + `storeFile`: the relative or absolute path to the key storage file that contains the private key used to sign the Android application.
+  + `storePassword`: the password used to access the key storage file.
+  + `keyAlias`: the alias of the key used to sign the application.
+  + `keyPassword`: the password used to access the key.
 
-- The credentials in JSON format to allow the fastlane action to connect to the Google Play Store console and upload the new build. To retrieve them, follow these steps:
+* The credentials in JSON format to allow the fastlane action to connect to the Google Play Store console and upload the new build. To retrieve them, follow these steps:
 
-  - Go to your Google Play Store console.
-  - In the Settings menu, select `API access`, then click `Create Service Account`
-  - Navigate to the provided Google Developers Console link in the dialog
-  - Click `Create Service Account` at the top of the Google Developers Console
-  - Provide the required details, then click `Create`
-  - Click `Select a role`, select `Service Accounts`, then click `Service Account User`
-  - In the Service Accounts dashboard, navigate to the Actions column, tap the menu for the service account that you created, then click `Create Key`
-  - Select JSON as the key type, then click `Save`
-  - Back on the Google Play Console, click `Done` to close the dialog
-  - Click on `Grant Access` for the newly added service account
-  - Make sure that the role of this service account has the permission to upload builds
-  - Click `Add User` to close the dialog
+  + Go to your Google Play Store console.
+  + In the Settings menu, select `API access`, then click `Create Service Account`
+  + Navigate to the provided Google Developers Console link in the dialog
+  + Click `Create Service Account` at the top of the Google Developers Console
+  + Provide the required details, then click `Create`
+  + Click `Select a role`, select `Service Accounts`, then click `Service Account User`
+  + In the Service Accounts dashboard, navigate to the Actions column, tap the menu for the service account that you created, then click `Create Key`
+  + Select JSON as the key type, then click `Save`
+  + Back on the Google Play Console, click `Done` to close the dialog
+  + Click on `Grant Access` for the newly added service account
+  + Make sure that the role of this service account has the permission to upload builds
+  + Click `Add User` to close the dialog
 
-Once you have all three elements in your folder, it's time to encrypt them. Indeed, this folder contains elements that are too sensitive to be referenced on git. Compress the folder, place the compressed folder in the android folder of your Flutter project, and execute the following command:
+Once you have all three elements in your folder, it's time to encrypt them. Indeed, this folder contains elements that are too sensitive to be referenced on git. 
+
+Place them in a folder named `android_keys` and compress it using the following command:
+
+```shell
+jar cfvM android_keys.zip android_keys
+```
+
+> The plugin will use `jar xvf android/android_keys.zip && mv android/android_keys/* android/` to extract the secret files.
+
+Then, encrypt the compressed folder using GPG.
 
 ```shell
 gpg --quiet --batch --yes --symmetric --passphrase="<android-key-passphrase>" --output android/android_keys.zip.gpg android/android_keys.zip