`npm audit` revealed some vulnerabilities:
```
scss-tokenizer <=0.4.2
Severity: high
Regular expression denial of service in scss-tokenizer - https://github.com/advisories/GHSA-7mwh-4pqv-wmr8
fix available via `npm audit fix --force`
Will install node-sass@4.5.3, which is a breaking change
node_modules/scss-tokenizer
sass-graph >=2.2.0
Depends on vulnerable versions of scss-tokenizer
node_modules/sass-graph
node-sass >=4.6.0
Depends on vulnerable versions of sass-graph
node_modules/node-sass
3 high severity vulnerabilities
```
We don't need node-sass, and sass-loader is just as happy using
another sass implementation. The preferred one is dart-sass which
is simply called sass in npm.
In the process, I also did an `npm update` just for good measure.
Input chunks from the client exceeding the buffer size would get
truncated. Now we communicate the size of the buffer to the webtty and
it will split the input into buffer sized chunks.
Fixes#1.
