Fix wenxin config in .env.template

[TJJ120635]

Fix wenxin config in .env.template

In dbgpt/_private/config.py, os.getenv("WEN_XIN_API_SECRET") is used to get API_SECRET.
But in .env.template WEN_XIN_SECRET_KEY is set.
Thus config.py cannot get correct API_KEY.

And PROXY_API is not needed because dbgpt/model/proxy/llms/wenxin.py automatically choose api url.

DB-GPT/dbgpt/model/proxy/llms/wenxin.py

Lines 63 to 83 in d906522

	def wenxin_generate_stream(
	model: ProxyModel, tokenizer, params, device, context_len=2048
	):
	MODEL_VERSION = {
	"ERNIE-Bot": "completions",
	"ERNIE-Bot-turbo": "eb-instant",
	}
	model_params = model.get_params()
	model_name = model_params.proxyllm_backend
	model_version = MODEL_VERSION.get(model_name)
	if not model_version:
	yield f"Unsupport model version {model_name}"
	proxy_api_key = model_params.proxy_api_key
	proxy_api_secret = model_params.proxy_api_secret
	access_token = _build_access_token(proxy_api_key, proxy_api_secret)
	headers = {"Content-Type": "application/json", "Accept": "application/json"}
	proxy_server_url = f"https://aip.baidubce.com/rpc/2.0/ai_custom/v1/wenxinworkshop/chat/{model_version}?access_token={access_token}"

Refer to issue #964

[csunny]

Thanks， LGTM

[fangyinc]

LGTM.