rest-openapi code generation does not work with Gradle

[jamesnetherton]

Bug description

There is a class loading issue. Seems resolving stuff via the Java ServiceLoader has some problems:

Caused by: java.util.ServiceConfigurationError: io.swagger.codegen.v3.CodegenConfig: Provider io.swagger.codegen.v3.generators.html.StaticHtmlCodegen could not be instantiated
        at io.swagger.codegen.v3.CodegenConfigLoader.forName(CodegenConfigLoader.java:19)
        at io.swagger.codegen.v3.config.CodegenConfigurator.loadCodegenConfig(CodegenConfigurator.java:673)
        at io.swagger.codegen.v3.config.CodegenConfigurator.toClientOptInput(CodegenConfigurator.java:518)
        at org.apache.camel.quarkus.component.rest.openapi.deployment.CamelQuarkusSwaggerCodegenProvider.trigger(CamelQuarkusSwaggerCodegenProvider.java:145)
        at io.quarkus.deployment.CodeGenerator.lambda$trigger$4(CodeGenerator.java:206)
        at io.quarkus.deployment.CodeGenerator.callWithClassloader(CodeGenerator.java:181)
        at io.quarkus.deployment.CodeGenerator.trigger(CodeGenerator.java:203)
        at io.quarkus.deployment.CodeGenerator.initAndRun(CodeGenerator.java:80)
        at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
        ... 23 more
Caused by: java.lang.NoClassDefFoundError: org/commonmark/parser/Parser
        at io.swagger.codegen.v3.utils.Markdown.<init>(Markdown.java:15)
        at io.swagger.codegen.v3.generators.html.StaticHtmlCodegen.<init>(StaticHtmlCodegen.java:160)
        at java.base/jdk.internal.reflect.DirectConstructorHandleAccessor.newInstance(DirectConstructorHandleAccessor.java:62)
        ... 32 more
Caused by: java.lang.ClassNotFoundException: org.commonmark.parser.Parser
        at io.quarkus.bootstrap.classloading.QuarkusClassLoader.loadClass(QuarkusClassLoader.java:569)
        at io.quarkus.bootstrap.classloading.QuarkusClassLoader.loadClass(QuarkusClassLoader.java:517)
        ... 35 more