[BUG][JAVA] scheme default to HTTP instead of HTTPS

Description

I generate a client using java generator with a OpenAPI declaration that is available through a https url. No "scheme" is available in this declaration but the documentation specify :

f the schemes is not included, the default scheme to be used is the one used to access the Swagger definition itself.

However, I get the following warning and the client is mapped to the wrong endpoint.

[WARNING] 'scheme' not defined in the spec (2.0). Default to [http] for server URL [http://scanr-api.enseignementsup-recherche.gouv.fr/api]

openapi-generator version

5.4.0

OpenAPI declaration file content or url

https://scanr-api.enseignementsup-recherche.gouv.fr/api/v2/api-docs

Steps to reproduce

mvn clean complie

The pom.xml that I use

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>apiclient</artifactId>
        <groupId>fr.theialand.insitu</groupId>
        <version>0.0.1-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>apiclient-scanr</artifactId>

    <description>ScanR client, returns Structures of research entities</description>

    <dependencies>
        <dependency>
            <groupId>fr.theialand.insitu</groupId>
            <artifactId>apiclient-common</artifactId>
            <version>0.0.1-SNAPSHOT</version>
        </dependency>

        <!-- Needed by the code generated by codegen -->
        <dependency>
            <groupId>io.swagger</groupId>
            <artifactId>swagger-annotations</artifactId>
            <version>1.6.2</version>
        </dependency>

        <!-- Needed by the generator > 4.1.0 for @Nullable unofficial annotations
 issue : https://github.com/OpenAPITools/openapi-generator/issues/7177 -->
        <dependency>
            <groupId>com.google.code.findbugs</groupId>
            <artifactId>jsr305</artifactId>
            <version>3.0.2</version>
        </dependency>

    </dependencies>

    <build>
        <plugins>
            <!-- Now we can generate the spring REST client, based on restTemplate -->
            <plugin>
                <groupId>org.openapitools</groupId>
                <artifactId>openapi-generator-maven-plugin</artifactId>
                <version>4.3.1</version>
                <executions>
                    <execution>
                        <goals>
                            <goal>generate</goal>
                        </goals>
                        <configuration>
                            <inputSpec>https://scanr-api.enseignementsup-recherche.gouv.fr/api/v2/api-docs</inputSpec>
<!--                            <inputSpec>${project.basedir}/src/main/resources/api-docs.json</inputSpec>-->
                            <generatorName>java</generatorName>
                            <skipValidateSpec>false</skipValidateSpec>

                            <configOptions>
                                <java8>true</java8>
                                <openApiNullable>false</openApiNullable>

                                <dateLibrary>legacy</dateLibrary> <!-- java.time new lib -->
                                <library>resttemplate</library> <!-- Spring http client -->
                                <serializationLibrary>jackson</serializationLibrary>
                                <sourceFolder>src/main/java</sourceFolder>
                            </configOptions>


                            <modelPackage>${project.groupId}.dataportal.api.scanr.model</modelPackage>
                            <apiPackage>${project.groupId}.dataportal.api.scanr.api</apiPackage>
                            <invokerPackage>${project.groupId}.dataportal.api.scanr.handler</invokerPackage>
                            <generateSupportingFiles>true</generateSupportingFiles>

                            <!-- other stuff generated by the codegen is buggy as sh*t , no need-->
                            <generateModelTests>false</generateModelTests>
                            <generateModelDocumentation>false</generateModelDocumentation>
                            <generateApiTests>false</generateApiTests>
                            <generateApiDocumentation>false</generateApiDocumentation>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

</project>

Start by running the openapi-generator Maven plugin with the supplied OpenAPI 2.0 URL and inspect where the Java generator handles a missing scheme. Compare the warning and generated endpoint with the declaration's HTTPS source URL. Done means generation defaults to the documented scheme behavior instead of mapping the client to HTTP.