chore: explicit exclusion old one gson dependency

[bednar]

Related to #342
Related to #338

Proposed Changes

This PR explicitly exclude dependencies to gson:2.8.x.

The Maven is not deterministic in resolving transient dependency. Maven chooses the first library it finds and it can be the older version (for more info see https://www.baeldung.com/maven-version-collision).

Dependency report

Before

...
[INFO] |  +- io.gsonfire:gson-fire:jar:1.8.5:compile
[INFO] |  |  \- (com.google.code.gson:gson:jar:2.8.6:compile - omitted for conflict with 2.9.0)
[INFO] |  +- com.squareup.retrofit2:converter-scalars:jar:2.9.0:compile
[INFO] |  |  \- (com.squareup.retrofit2:retrofit:jar:2.9.0:compile - omitted for duplicate)
[INFO] |  +- com.squareup.retrofit2:converter-gson:jar:2.9.0:compile
[INFO] |  |  +- (com.squareup.retrofit2:retrofit:jar:2.9.0:compile - omitted for duplicate)
[INFO] |  |  \- (com.google.code.gson:gson:jar:2.8.5:compile - omitted for conflict with 2.9.0)
[INFO] |  \- com.google.code.findbugs:jsr305:jar:3.0.2:compile
...

After

[INFO] |  +- io.gsonfire:gson-fire:jar:1.8.5:compile
[INFO] |  +- com.squareup.retrofit2:converter-scalars:jar:2.9.0:compile
[INFO] |  |  \- (com.squareup.retrofit2:retrofit:jar:2.9.0:compile - omitted for duplicate)
[INFO] |  +- com.squareup.retrofit2:converter-gson:jar:2.9.0:compile
[INFO] |  |  \- (com.squareup.retrofit2:retrofit:jar:2.9.0:compile - omitted for duplicate)
[INFO] |  \- com.google.code.findbugs:jsr305:jar:3.0.2:compile

Checklist

• Rebased/mergeable
• mvn test completes successfully
• Commit messages are in semantic format
• Sign CLA (if not already signed)