Update pom.xml

[AndreyJVM]

What has been changed:

All dependency versions have been moved to the <properties> block:

• Now all versions are in one place, which makes it easier to manage and update them.
• Each version has a clear name, for example, <flyway-version>, <postgresql-version>, etc.

Using variables in dependencies:

• In the <dependencies> section, all versions have been replaced with variables from <properties>.

Improved readability:

• Now it's easy to see which library and which version is being used just by looking at the <properties> block.

This approach makes a file pom.xml more convenient for support and scaling.

[BrapiCoordinatorSelby]

Hey @AndreyJVM Thanks for the contribution! How did you find this project?

[AndreyJVM]

I was looking for interesting and actively developing projects on "#Java"