Error Plugin: front: files attribute must be specified in package.json

**Intended outcome:**

Executing `service:push`.

**Actual outcome:**

Error:
`
DEBUG=* node_modules/.bin/apollo service:push ...
@oclif/config reading core plugin /home/user123/src/proj +0ms
@oclif/config loadJSON /home/user123/src/proj/package.json +0ms
@oclif/config loadJSON /home/user123/src/proj/oclif.manifest.json +3ms
(node:42434) Error Plugin: front: files attribute must be specified in /home/user123/src/proj/package.json
module: @oclif/config@1.17.0
plugin: front
root: /home/user123/src/proj
See more details with DEBUG=*
Error Plugin: front: files attribute must be specified in /home/user123/src/proj/package.json
at Plugin.warn (/home/user123/src/proj/node_modules/@oclif/config/lib/plugin.js:247:19)
at Plugin.load (/home/user123/src/proj/node_modules/@oclif/config/lib/plugin.js:101:18)
at async Config.load (/home/user123/src/proj/node_modules/@oclif/config/lib/config.js:41:9)
at async Object.load (/home/user123/src/proj/node_modules/@oclif/config/lib/config.js:374:5)
at async Function.Command.run (/home/user123/src/proj/node_modules/@oclif/command/lib/command.js:160:20)
module: @oclif/config@1.17.0
plugin: front
root: /home/user123/src/proj
See more details with DEBUG=*
@oclif/config loadJSON /home/user123/src/proj/.oclif.manifest.json +2ms
@oclif/config reading user plugins pjson /home/ec2-user/.local/share/front/package.json +0ms
@oclif/config loadJSON /home/ec2-user/.local/share/front/package.json +2ms
@oclif/config config done +1ms
@oclif/config start init hook +3ms
@oclif/config init hook done +0ms
@oclif/config start command_not_found hook +0ms
@oclif/config command_not_found hook done +0ms
Error: command service:push not found
at Config.runCommand (/home/user123/src/proj/node_modules/@oclif/config/lib/config.js:169:19)
at async Main.run (/home/user123/src/proj/node_modules/@oclif/command/lib/main.js:27:9)
at async Main._run (/home/user123/src/proj/node_modules/@oclif/command/lib/command.js:43:20)
`

**How to reproduce the issue:**

Install apollo locally with command: `npm install --save-dev apollo` and try to use.

**Versions**

"apollo": "^2.32.5"

Start by reproducing the failure from package.json with `npm install --save-dev apollo`, then run the `service:push` entry point and inspect the reported @oclif/config error. Done means the locally installed Apollo CLI recognizes `service:push` without the package.json plugin error or the subsequent command-not-found failure.

Written by the indexing model from the issue text.