regression: CLI processing of globs

The prior version of HTTPSnippet allowed processing of globs on the CLI as follows:

httpsnippet ./*.json --target node --client request --output ./snippets

$ tree snippets/
snippets/
├── endpoint-1.js
├── endpoint-2.js
└── endpoint-3.js

I wasn't aware of this prior functionality (and there were no tests covering it) so it was missed.

Shouldn't be too terrible to add back. Let's have some tests for it this time, too.

Reproduction steps

run the following:

./bin/httpsnippet src/fixtures/requests/*.json --target node --client unirest --output ./example

And it returns this input:

Unknown arguments: src/fixtures/requests/application-json.json, src/fixtures/requests/cookies.json, src/fixtures/requests/custom-method.json, src/fixtures/requests/full.json, src/fixtures/requests/headers.json, src/fixtures/requests/https.json, src/fixtures/requests/jsonObj-multiline.json, src/fixtures/requests/jsonObj-null-value.json, src/fixtures/requests/multipart-data.json, src/fixtures/requests/multipart-file.json, src/fixtures/requests/multipart-form-data.json, src/fixtures/requests/multipart-form-data-no-params.json, src/fixtures/requests/nested.json, src/fixtures/requests/query.json, src/fixtures/requests/short.json, src/fixtures/requests/text-plain.json

When it should, instead, process all of those files.

bin/httpsnippet の CLI エントリーポイントから始め、src/fixtures/requests/*.json に対して glob コマンドを使って失敗を再現します。引数がどのように解析され、単一の入力がどのように処理されるかを追跡し、その後、複数の glob 対象ファイルをカバーする CLI テストを追加して、unknown-arguments エラーではなく各入力から出力が生成されることを確認します。