[BUG] Unable to build project on MacOS

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?
• [Optional] Sponsorship to speed up the bug fix or feature request (example)

Description

Unable to complete mvn clean install on the project. However, I am able to successfully execute mvn clean package

openapi-generator version

I'm building the master branch at the tip of commit 484b87f22a79779ec75f04a672175b702cad7fea

Steps to reproduce

1. Clone the git repository, checkout the master branch.
2. Install the specified versions of dependencies. Here is the information about the environment:

Observed error log: install-error-log.txt

Related issues/PRs

I could not find related issues. However, other developers have stumbled across this issue, albeit unsuccessfully. Here is a reference to a similar bug (referencing different gradle version) in a README file.

Suggest a fix

This appears to be a mismatch between the gradle version and the java runtime, but I don't know how to fix that.
I'd like to draw your attention to this snippet from the above error log:

FAILURE: Build failed with an exception.

* What went wrong:
Could not open settings generic class cache for settings file '/Users/ckeshavabs/openapi-generator/modules/openapi-generator-gradle-plugin/settings.gradle' (/Users/ckeshavabs/.gradle/caches/7.6.4/scripts/qtv78r5dx5edqhhhf13bv6o).
> BUG! exception in phase 'semantic analysis' in source unit '_BuildScript_' Unsupported class file major version 65

* Try:
> Run with --stacktrace option to get the stack trace.
> Run with --info or --debug option to get more log output.
> Run with --scan to get full insights.

* Get more help at https://help.gradle.org

Start by running the reported mvn clean install reproduction on macOS and reading install-error-log.txt, focusing on the settings.gradle failure and unsupported class file version. Compare the project’s Gradle guidance in README.md around line 408 with the reported environment. Done means the project builds successfully with mvn clean install without the class-version error.