clarify meaning of subject in SCS-0004 (#1156)

* clarify meaning of subject in SCS-0004
* use plural form

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Signed-off-by: Marvin Frommhold <depressiveRobot@users.noreply.github.com>

Author: depressiveRobot

Standards/scs-0004-v1-achieving-certification.md

@@ -20,7 +20,7 @@ As operator, I want to obtain a certificate with the scope SCS-compatible IaaS o
 
 0. Certificates are issued by the SCS certification assessment body. This is either the _Forum SCS-Standards_, part of the Open Source Business Alliance e.V. (OSBA), or an organization appointed by the _Forum SCS-Standards_ . An interested party has to apply for certification with this body, which in turn determines the rules that govern what parties are eligible for application (fees may apply).
 
-1. Each certificate issued pertains to a given combination of subject (i.e., cloud environment), scope (such as _SCS-compatible IaaS_), and version of that scope. The certificate is only valid for that combination and for the time frame that ends when the scope expires, or for six months if the expiration date for the scope is not yet fixed.
+1. Each certificate issued pertains to a given combination of subject (specific cloud environment including IaaS regions or KaaS configurations), scope (such as _SCS-compatible IaaS_ or _SCS-compatible KaaS_), and version of that scope. The certificate is only valid for that combination and for the time frame that ends when the scope expires, or for six months if the expiration date for the scope is not yet fixed.
 
 2. The operator MUST ensure that the official [SCS compliance test suite](https://github.com/SovereignCloudStack/standards/tree/main/Tests) (which does not require admin privileges) is run at regular intervals and that all tests pass. The operator MUST submit the resulting reports to the [SCS compliance monitor](https://github.com/SovereignCloudStack/standards/tree/main/compliance-monitor).