Update port for Docker development environment in README

[encg]

What set up are you using

• Cloud Hosted Version
• Self Hosted

Describe the bug
The instructions for the Docker development installation currently point to Leantime living on port 8080, but this is incorrect and should be port 8090 instead.

The port changed between these two in the docker-compose.yaml file and this may not have been updated in the readme.

To Reproduce
Steps to reproduce the behavior:

1. Install the development environment via Docker
2. Navigate to localhost:8080 and localhost:8090

Expected behavior
Expect Leantime on localhost:8080 per readme, but it is on localhost:8090.

Leantime Version
v2.4.1

Server
Docker development environment

PHP / MySQL Version
Docker development environment

Additional context
N/A

[CLAassistant]

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