Python 3.6 is EOL

Python 3.6 reached EOL in December, here is the current split by version for arrow usage.

| category | percent | downloads |
|:---------|--------:|----------:|
| 3.7 | 38.26% | 1,910,775 |
| 3.8 | 32.76% | 1,635,938 |
| 3.6 | 12.85% | 641,712 |
| 3.9 | 6.48% | 323,713 |
| null | 3.70% | 185,035 |
| 2.7 | 3.07% | 153,354 |
| 3.10 | 2.26% | 112,810 |
| 3.5 | 0.51% | 25,236 |
| 3.4 | 0.11% | 5,477 |
| 3.11 | 0.01% | 404 |
| Total | | 4,994,454 |

Date range: 2021-12-01 - 2021-12-31

The issue provides Python-version usage data but names no files, tests, or entry points. First inspect the project's Python-version declarations and CI configuration, then confirm the intended support boundary; done means the repository consistently reflects that decision and its checks pass.

Written by the indexing model from the issue text.