package.json: Fix eslint scripts
package.json: Fix eslint scripts

`--ext` disables the internal `*.js` default extension, so explicitly
add it. This actually includes .js files in `npm run eslint` and
`eslint:fix`.

Note that this did not affect calling eslint from webpack, *.js files
get included there properly.

andreasn/cockpit,moraleslazaro/cockpit,cockpituous/cockpit,cockpituous/cockpit,garrett/cockpit,cockpit-project/cockpit,andreasn/cockpit,moraleslazaro/cockpit,andreasn/cockpit,mvollmer/cockpit,deryni/cockpit,mvollmer/cockpit,cockpit-project/cockpit,deryni/cockpit,andreasn/cockpit,cockpituous/cockpit,moraleslazaro/cockpit,cockpituous/cockpit,deryni/cockpit,andreasn/cockpit,garrett/cockpit,moraleslazaro/cockpit,mvollmer/cockpit,deryni/cockpit,garrett/cockpit,moraleslazaro/cockpit,mvollmer/cockpit,garrett/cockpit,deryni/cockpit,martinpitt/cockpit,martinpitt/cockpit,andreasn/cockpit,deryni/cockpit,martinpitt/cockpit,martinpitt/cockpit,moraleslazaro/cockpit,andreasn/cockpit,cockpit-project/cockpit,martinpitt/cockpit,moraleslazaro/cockpit,deryni/cockpit,mvollmer/cockpit,garrett/cockpit,cockpit-project/cockpit,cockpituous/cockpit,cockpituous/cockpit,cockpit-project/cockpit