about 200 local variables limitation

[RocFang]

Hello, @spacewander ,

The problem of 200 local variables limitation often occur to us when the json schema file geting bigger.
error info like:

main function has more than 200 local variables

I found 2 relative record from other repo:

1. fix(*) ability to generate >200 local vars Tieske/lua-resty-ljsonschema#2
2. main function has more than 200 local variables jdesgats/ljsonschema#10

can we do this workaround too? thanks.

[membphis]

welcome PR, we can cherry-pick the commit ^_^

[RocFang]

@membphis I have made a pr,
#41

thanks for review.