Update ESLint CI image.
Switch from singapore/lint-condo to my fork which has been updated, ewlsh/lint-condo.
Changes:
- Node v6 -> Node v12
- ESLint 5.5 -> ESLint 7.2.x
- Many security updates to the various linter packages.
- Add a
package-lock.json
to ensure package versions.
The images are auto-built on Docker Hub here.