A typo in src/check-token.ts. Should be 'authorization' instead of 'authentication'

[jfshark]

Hello!

I was using the emulator to test our Azure SaaS integration development. And when I switched to azure token usage ("REQUIRE_AUTH": "true"), it stopped working and gave me 401 all the time. As it was in the docker desktop, I had to run it locally to be able to debug. And found that in line 33 of check-token.js there is 'req.headers.authentication' instead of 'req.headers.authorization'. It does not work with correct tokens. After fixing it works as expected