fix(integ-runner): array arguments aren't recognizing multiple options (#21763)

I don't know why I was specifying `nargs: 1` for array arguments. This
tells yargs to only accept a single argument. You can no provide
multiple options, i.e.

```
yarn integ --regions us-east-1 us-east-2
```

re #20384


----

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*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

Author: corymhall

packages/@aws-cdk/integ-runner/lib/cli.ts

@@ -22,9 +22,9 @@ async function main() {
     .option('dry-run', { type: 'boolean', default: false, desc: 'do not actually deploy the stack. just update the snapshot (not recommended!)' })
     .option('update-on-failed', { type: 'boolean', default: false, desc: 'rerun integration tests and update snapshots for failed tests.' })
     .option('force', { type: 'boolean', default: false, desc: 'Rerun all integration tests even if tests are passing' })
-    .option('parallel-regions', { type: 'array', desc: 'Tests are run in parallel across these regions. To prevent tests from running in parallel, provide only a single region', nargs: 1, default: [] })
+    .option('parallel-regions', { type: 'array', desc: 'Tests are run in parallel across these regions. To prevent tests from running in parallel, provide only a single region', default: [] })
     .options('directory', { type: 'string', default: 'test', desc: 'starting directory to discover integration tests. Tests will be discovered recursively from this directory' })
-    .options('profiles', { type: 'array', desc: 'list of AWS profiles to use. Tests will be run in parallel across each profile+regions', nargs: 1, default: [] })
+    .options('profiles', { type: 'array', desc: 'list of AWS profiles to use. Tests will be run in parallel across each profile+regions', default: [] })
     .options('max-workers', { type: 'number', desc: 'The max number of workerpool workers to use when running integration tests in parallel', default: 16 })
     .options('exclude', { type: 'boolean', desc: 'Run all tests in the directory, except the specified TESTs', default: false })
     .options('from-file', { type: 'string', desc: 'Read TEST names from a file (one TEST per line)' })