[REQ] Support multiple YAML files for openapi-generator-maven-plugin

I have a project that needs to use multiple YAML files, but the inputSpec doesn't support this.
I try a workaround solution by adding multiple executions of the maven plugin into the pom, this issue can be temporarily solved.
But in case I need to generate for many more files (YAML1, YAML2, YAML3,...), and in case my execution contains a big block of code like below:

<execution>
	<goals>
		<goal>generate</goal>
	</goals>
	<configuration>
		<inputSpec>${basedir}/api-spec/${swagger.version}/example1.yaml</inputSpec>
		<output>${basedir}</output>
		<templateDirectory>${basedir}/template/${swagger.version}</templateDirectory>
		<additionalProperties>apiVersion=${swagger.version},useApiAnnotation=false</additionalProperties>
		<generateSupportingFiles>false</generateSupportingFiles>
		<generateModelTests>false</generateModelTests>
		<generateApiTests>false</generateApiTests>
		<generateModelDocumentation>false</generateModelDocumentation>
		<generateApiDocumentation>false</generateApiDocumentation>
		<generatorName>jaxrs-spec</generatorName>
		<configOptions>
			<sourceFolder>src/main/java</sourceFolder>
			<implFolder>src/main/java</implFolder>
			<apiPackage>${swagger.api.package}</apiPackage>
			<interfaceOnly>true</interfaceOnly>
			<java8>true</java8>
			<modelPackage>${swagger.model.package}</modelPackage>
			<useSwaggerAnnotations>false</useSwaggerAnnotations>
			<generatePom>false</generatePom>
			<useBeanValidation>false</useBeanValidation>
		</configOptions>
		<typeMappings>
			<typeMapping>Date=String</typeMapping>
			<typeMapping>LocalDate=String</typeMapping>
		</typeMappings>
	</configuration>
</execution>
<execution>
           ..
</execution>
<execution>
           ...
</execution>

The above workaround is not good, can you support us for a feature that supports multiple YAML files?

Start with the openapi-generator-maven-plugin configuration and its inputSpec handling. Define how multiple YAML files should be supplied and what generation behavior is expected, then verify that users no longer need repeated Maven executions for each specification.