jwt sgin err when typ is JWE

[Steven201314]

When test this code , in openresty it aborted a error follow
local jwt_token = jwt:sign( "lua-resty-jwt1", { header={typ="JWE", alg="dir" , enc = 'A128CBC-HS256'}, payload={foo="bar"} } ) ngx.print("jwt_token:")
`
2019/10/30 23:59:07 [error] 2369#0: *246 lua entry thread aborted: runtime error: unknown reason
stack traceback:
coroutine 0:
[C]: in function 'error'
/usr/share/lua/5.1/resty/jwt.lua:202: in function 'derive_keys'
/usr/share/lua/5.1/resty/jwt.lua:407: in function 'sign'

`

[cdbattags]

check out the fork at https://github.com/cdbattags/lua-resty-jwt

this repo has been more or less "deprecated" by the community

[cdbattags]

LuaRocks has the above fork as the main in the registry https://luarocks.org/modules/cdbattags/lua-resty-jwt