Example configuration in README causes warning

[marcelm]

Thank you for providing this action!

The example configuration shown under the “Usage” heading in the README uses an old micromamba version:

micromamba-version: '1.3.1-0'

When run, this warning is printed:

Warning: You are using a micromamba version < 1.4.5-0 and initialize the shell.
This is behavior is deprecated. Please update the micromamba version. For further
informations, see https://github.com/mamba-org/setup-micromamba/pull/107

I admit I often just copy the example configurations for GitHub Actions assuming that they are up to date. It would be nice to change this to a version that does not cause a warning or perhaps even latest.

Maybe the https://github.com/mamba-org/micromamba-releases/releases URL could also be listed somewhere in the README (it is a bit hidden in action.yml at the moment).