Enable four new ESLint rules

[ottaviohartman]

Add some rules that were likely lost during the transition from JSHint to ESLint. #5344

These rules are the only of #5456 which do not require code changes in any way.

• guard-for-in
• no-caller
• no-floating-decimal
• no-new

[ottaviohartman]

@mramato I put these in Cesium's .eslintrc.json. Should they go in the shareable config instead?

[mramato]

Yes, they should go in the shareable config. Also, create a 2.0.0 version in CHANGES.md for the shareable config and and add a line for each new rule. Something like Enabled guard-for-in. where the rule links to esline like you did above. When #5456 is done, we'll publish the new version.

[ottaviohartman]

As it turns out, only one of these rules (no-floating-decimal) was not enabled by default.

[mramato]

Thanks.