OpenAI: gpt-oss-20b

Added the new OpenAI: gpt-oss-20b

Author: cerebrux

.env

@@ -51,6 +51,7 @@ OPENROUTER_API_KEY=
 #OPENROUTER_MODEL=nvidia/llama-3.1-nemotron-ultra-253b-v1:free
 #OPENROUTER_MODEL=nvidia/llama-3.3-nemotron-super-49b-v1:free
 #OPENROUTER_MODEL=openrouter/cypher-alpha:free
+#OPENROUTER_MODEL=openai/gpt-oss-20b:free
 #OPENROUTER_MODEL=qwen/qwen-2.5-72b-instruct:free
 #OPENROUTER_MODEL=qwen/qwen-2.5-coder-32b-instruct:free
 #OPENROUTER_MODEL=qwen/qwen3-14b:free
@@ -69,4 +70,4 @@ OPENROUTER_API_KEY=
 #OPENROUTER_MODEL=thudm/glm-4-32b:free
 #OPENROUTER_MODEL=thudm/glm-z1-32b:free
 #OPENROUTER_MODEL=tngtech/deepseek-r1t-chimera:free
-#OPENROUTER_MODEL=tngtech/deepseek-r1t2-chimera:free
+#OPENROUTER_MODEL=tngtech/deepseek-r1t2-chimera:free