CI for language switch: GPT-OSS 20B

Author: ariya

.github/workflows/lang-switch.yml

@@ -14,6 +14,7 @@ jobs:
         model:
           - google/gemma-3-4b-it                         # $0.0200/$0.0400 [ 128K]
           - z-ai/glm-4-32b                               # $0.1000/$0.1000 [ 128K]
+          - openai/gpt-oss-20b                           # $0.0300/$0.1400 [ 128K]
           - openai/gpt-5-nano                            # $0.0500/$0.4000 [1000K]
 
     steps: