docs(feature-flags): create concrete documentation (#594)

Co-authored-by: heitorlessa <lessa@amazon.co.uk>

Author: Alex

Diff for: README.md

@@ -25,6 +25,7 @@ A suite of Python utilities for AWS Lambda functions to ease adopting best pract
 * **[Event source data classes](https://awslabs.github.io/aws-lambda-powertools-python/latest/utilities/data_classes/)** - Data classes describing the schema of common Lambda event triggers
 * **[Parser](https://awslabs.github.io/aws-lambda-powertools-python/latest/utilities/parser/)** - Data parsing and deep validation using Pydantic
 * **[Idempotency](https://awslabs.github.io/aws-lambda-powertools-python/latest/utilities/idempotency/)** - Convert your Lambda functions into idempotent operations which are safe to retry
+* **[Feature Flags](./utilities/feature_flags.md)** - A simple rule engine to evaluate when one or multiple features should be enabled depending on the input
 
 ### Installation
 

Diff for: aws_lambda_powertools/utilities/feature_flags/appconfig.py

@@ -21,7 +21,7 @@ def __init__(
         environment: str,
         application: str,
         name: str,
-        cache_seconds: int,
+        max_age: int = 5,
         sdk_config: Optional[Config] = None,
         envelope: Optional[str] = "",
         jmespath_options: Optional[Dict] = None,
@@ -36,8 +36,8 @@ def __init__(
             AppConfig application name, e.g. 'powertools'
         name: str
             AppConfig configuration name e.g. `my_conf`
-        cache_seconds: int
-            cache expiration time, how often to call AppConfig to fetch latest configuration
+        max_age: int
+            cache expiration time in seconds, or how often to call AppConfig to fetch latest configuration
         sdk_config: Optional[Config]
             Botocore Config object to pass during client initialization
         envelope : Optional[str]
@@ -49,7 +49,7 @@ def __init__(
         self.environment = environment
         self.application = application
         self.name = name
-        self.cache_seconds = cache_seconds
+        self.cache_seconds = max_age
         self.config = sdk_config
         self.envelope = envelope
         self.jmespath_options = jmespath_options

Diff for: aws_lambda_powertools/utilities/feature_flags/feature_flags.py

@@ -24,7 +24,7 @@ def __init__(self, store: StoreProvider):
             environment="test",
             application="powertools",
             name="test_conf_name",
-            cache_seconds=300,
+            max_age=300,
             envelope="features"
         )
 

Diff for: docs/index.md

@@ -212,6 +212,7 @@ aws serverlessrepo list-application-versions \
 [Event source data classes](./utilities/data_classes.md) | Data classes describing the schema of common Lambda event triggers
 [Parser](./utilities/parser.md) | Data parsing and deep validation using Pydantic
 [Idempotency](./utilities/idempotency.md) | Idempotent Lambda handler
+[Feature Flags](./utilities/feature_flags.md) | A simple rule engine to evaluate when one or multiple features should be enabled depending on the input
 
 ## Environment variables