Use octet-stream content type as default for s3 uploads

Created by: andrcuns

Fixes: https://github.com/andrcuns/allure-report-publisher/issues/489

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Allure report

allure-report-publisher generated test report!

rspec: ✅ test report for 1689d0d4

+----------------------------------------------------------------+
|                       behaviors summary                        |
+-----------+--------+--------+---------+-------+-------+--------+
|           | passed | failed | skipped | flaky | total | result |
+-----------+--------+--------+---------+-------+-------+--------+
| commands  | 75     | 0      | 0       | 0     | 75    | ✅     |
| providers | 60     | 0      | 0       | 0     | 60    | ✅     |
| generator | 6      | 0      | 0       | 0     | 6     | ✅     |
| helpers   | 123    | 0      | 0       | 0     | 123   | ✅     |
| uploaders | 57     | 0      | 0       | 0     | 57    | ✅     |
| cli       | 3      | 0      | 0       | 0     | 3     | ✅     |
+-----------+--------+--------+---------+-------+-------+--------+
| Total     | 324    | 0      | 0       | 0     | 324   | ✅     |
+-----------+--------+--------+---------+-------+-------+--------+