Redis-dict

updated readme, test-requirement bump

Added datetime timedelta for expiration during initialization and within the context manager.
Bumped the test-requirement version of cryptography.
Great thanks to Pydes-boop for incorporating timedeltas for expiration during initialization and in the context manager.

passed:

mypy --strict redis_dict.py
pylama redis_dict.py -i E501

Added Redis configuration example to Readme
Updated "how to" with Redis configuration

* Setup guide for Redis encryption.
* Minor wording changes to the README for improved clarity.
* An example illustrating the use of 'preserve timeout' for keys, developed in collaboration with cterrazas2."

* bumped package versions for security
* small update for readme

In this release, a new feature has been added to the RedisDict functionality: Preserve Expiration. This feature enables the user to maintain the existing TTL (Time to Live) value of a key when it is updated, rather than resetting it to the default or global expire time.

Now, when an existing key is updated and preserve_expiration is set to True, the current TTL of the key is preserved. This effectively allows keys to retain their original expiration settings even after their values have been updated. This provides greater flexibility and control over individual key expiration settings in your Redis data store.

The new feature has been thoroughly tested to ensure its reliable functionality. The unittests added cover various scenarios of using the preserve_expiration configuration parameter.

Special thanks to GitHub user cterrazas2, who not only brought this issue to attention, but also contributed to the solution by providing the initial code for this feature. The involvement has been invaluable in making this enhancement possible.