Enforce the use of `let` and `const` by using elsint rules.
When creating the eslint configuration, I had assumed that
`extends: eslint:recommended` would have covered this, but
apparently not!
Existing usage of `var` fixed with `npm run lint -- --fix`.
Fixes: https://github.com/cloudevents/sdk-javascript/issues/97
Signed-off-by: Lance Ball <lball@redhat.com>
Automatically fixed > 2000 issues. The remaining 200+ issues need
to be fixed by hand. Additionally, all strings are double quotes
which is not typically standard and I wonder about fixing that too.
Signed-off-by: Lance Ball <lball@redhat.com>