fix: package.json to reduce vulnerabilities
fix: package.json to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/npm:tunnel-agent:20170305
- https://snyk.io/vuln/npm:ws:20160920

Latest report for ofrbg/tsukibot:
https://snyk.io/test/github/ofrbg/tsukibot
OFRBG/TsukiBot