CI: Don't publish to CodeClimate for forks

The CI fails for forks, so let's skip this step for forks:
/home/runner/work/peerjs-server/peerjs-server/cc-reporter before-build
ℹ️ 'coverageCommand' not set, so skipping building coverage report!
/home/runner/work/peerjs-server/peerjs-server/cc-reporter after-build --exit-code 0
Error: you must supply a CC_TEST_REPORTER_ID ENV variable or pass it via the -r flag
Usage:
  cc-test-reporter after-build [flags]

Flags:
  -s, --batch-size int               batch size for source files (default 500)
  -e, --coverage-endpoint string     endpoint to upload coverage information to (default "https://api.codeclimate.com/v1/test_reports")
  -t, --coverage-input-type string   type of input source to use [clover, cobertura, coverage.py, excoveralls, gcov, gocov, jacoco, lcov, lcov-json, simplecov, xccov, dotcover]
      --exit-code int                exit code of the test run
  -r, --id string                    reporter identifier
      --insecure                     send coverage insecurely (without HTTPS)
  -p, --prefix string                the root directory where the coverage analysis was performed (default "/home/runner/work/peerjs-server/peerjs-server")

Global Flags:
  -d, --debug   run in debug mode

Error: The process '/home/runner/work/peerjs-server/peerjs-server/cc-reporter' failed with exit code 255
/home/runner/work/_actions/paambaati/codeclimate-action/v5.0.0/node_modules/@actions/exec/lib/toolrunner.js:592
                error = new Error(`The process '${this.toolPath}' failed with exit code ${this.processExitCode}`);
                        ^

Error: The process '/home/runner/work/peerjs-server/peerjs-server/cc-reporter' failed with exit code 255
    at ExecState._setResult (/home/runner/work/_actions/paambaati/codeclimate-action/v5.0.0/node_modules/@actions/exec/lib/toolrunner.js:592:25)
    at ExecState.CheckComplete (/home/runner/work/_actions/paambaati/codeclimate-action/v5.0.0/node_modules/@actions/exec/lib/toolrunner.js:575:1[8](https://github.com/hugovk/peerjs-server/actions/runs/8131272338/job/22220402715#step:8:9))
    at ChildProcess.<anonymous> (/home/runner/work/_actions/paambaati/codeclimate-action/v5.0.0/node_modules/@actions/exec/lib/toolrunner.js:46[9](https://github.com/hugovk/peerjs-server/actions/runs/8131272338/job/22220402715#step:8:10):27)
    at ChildProcess.emit (node:events:513:28)
    at maybeClose (node:internal/child_process:1[10](https://github.com/hugovk/peerjs-server/actions/runs/8131272338/job/22220402715#step:8:11)0:[16](https://github.com/hugovk/peerjs-server/actions/runs/8131272338/job/22220402715#step:8:17))
    at Process.ChildProcess._handle.onexit (node:internal/child_process:304:5)
Error: 🚨 CC Reporter after-build checkin failed!
https://github.com/hugovk/peerjs-server/actions/runs/8131272338
peers / peerjs-server

CI: Don't publish to CodeClimate for forks #447
