Add soft_fail option to AMD CI configuration

Author: nHackel

.buildkite/pipeline.yml

@@ -34,4 +34,5 @@ steps:
       Pkg.add("AMDGPU")
       Pkg.instantiate()
       include("test/gpu/rocm.jl")'
-    timeout_in_minutes: 30
+    timeout_in_minutes: 30
+    soft_fail: true