[Bug]: Cannot run Gradlew due to :buildSrc:compileGroovy error

### What happened?

I've followed the set up steps here: https://beam.apache.org/contribute/get-started-contributing/ and my `./gradlew :checkSetup` is failing due to the following:

```
./gradlew :checkSetup
Starting a Gradle Daemon, 1 incompatible Daemon could not be reused, use --status for details
> Task :buildSrc:compileGroovy FAILED

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':buildSrc:compileGroovy'.
> BUG! exception in phase 'semantic analysis' in source unit '/Users/arwin.tio/projects/beam/buildSrc/src/main/groovy/org/apache/beam/gradle/BeamJenkinsPlugin.groovy' Unsupported class file major version 61

* 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

Deprecated Gradle features were used in this build, making it incompatible with Gradle 7.0.
Use '--warning-mode all' to show the individual deprecation warnings.
See https://docs.gradle.org/6.9.1/userguide/command_line_interface.html#sec:command_line_warnings

BUILD FAILED in 7s
```

I am on a Mac OSX:

```
uname -a
Darwin C02DQ2E0MD6R 20.6.0 Darwin Kernel Version 20.6.0: Thu Sep 29 20:15:11 PDT 2022; root:xnu-7195.141.42~1/RELEASE_X86_64 x86_64
```

On Java 17:
```
java -version
openjdk version "17.0.2" 2022-01-18
OpenJDK Runtime Environment (build 17.0.2+8-86)
OpenJDK 64-Bit Server VM (build 17.0.2+8-86, mixed mode, sharing)
```

and:
```
./gradlew --version

------------------------------------------------------------
Gradle 6.9.1
------------------------------------------------------------

Build time: 2021-08-20 11:15:18 UTC
Revision: f0ddb54aaae0e44f0a7209c3c0274d506ea742a0

Kotlin: 1.4.20
Groovy: 2.5.12
Ant: Apache Ant(TM) version 1.10.9 compiled on September 27 2020
JVM: 17.0.2 (Oracle Corporation 17.0.2+8-86)
OS: Mac OS X 11.7.1 x86_64
```

### Issue Priority

Priority: 2

### Issue Component

Component: build-system