tests: lib: uoscore: Add missing testcase.yaml

It was overlooked somehow, that usocore tests did not have testcase.yaml
file, and therefore were not executed by Twister. This commit fixes it.

Signed-off-by: Robert Lubos <[email protected]>

Author: rlubos

tests/lib/uoscore/testcase.yaml

@@ -0,0 +1,6 @@
+tests:
+  libraries.uoscore:
+    min_flash: 240
+    tags: net crypto uoscore
+    integration_platforms:
+      - qemu_x86