Revert "removing s390x as a build target"

This reverts commit a6fbf5e.

Author: ckhordiasma

.tekton/odh-trustyai-nemo-guardrails-server-pull-request.yaml

@@ -43,14 +43,15 @@ spec:
     - linux/x86_64
     - linux-m2xlarge/arm64
     - linux/ppc64le
+    - linux/s390x
   - name: prefetch-input
     value: |
       [{
         "type": "pip",
         "path": ".",
         "requirements_files": ["requirements.txt", "requirements-models.txt"],
         "requirements_build_files": ["requirements-build.txt"],
-        "binary": {"arch": "x86_64,aarch64,ppc64le"}
+        "binary": {"arch": "x86_64,aarch64,ppc64le,s390x"}
       },
       {
         "type": "generic",