SimpleServcieInstance should override getScheme()

I'm submitting a bugreport for

• spring-cloud-commons
• class org.springframework.cloud.client.discovery.simple.SimpleDiscoveryProperties

Versions used:

• spring-boot: 2.3.3
• spring-cloud: Hoxton.SR7
• spring-cloud-commons: 2.2.4.RELEASE

When using SimpleDiscoveryClient, non-HTTPS Urls do not work, they are always resolved as https:// URLs.
We are using https in production, but http in Tests to avoid the need to setup certificates for localhost.
There are workarounds, but I think this is a bug that should be fixed in spring-cloud-commons

e.g.

"spring.cloud.discovery.client.simple.instances.foo-service[0].uri= http://localhost:8889",
"spring.cloud.discovery.client.simple.instances.foo-service[0].secure = false",

foo-service is always resolved as https://localhost:8889, because SimpleServcieInstance (inner class of SimpleServiceProperties) does not override getScheme().

LoadBalancerUriTools calls getScheme() and in case of SimpleServiceInstance always receives null and thus always sets Scheme to https.

Proposed fix for org.springframework.cloud.client.discovery.simple.SimpleDiscoveryProperties#SimpleServiceInstance

public String getScheme() { return this.isSecure() ? "https" : "http"; }