Fix supported Python versions in README (#56734)

3.9 was dropped and 3.13 support was included.

(cherry picked from commit c47b1ae)

Author: kaxil

README.md

@@ -101,7 +101,7 @@ Apache Airflow is tested with:
 
 |            | Main version (dev)     | Stable version (3.0.6) |
 |------------|------------------------|------------------------|
-| Python     | 3.10, 3.11, 3.12, 3.13 | 3.9, 3.10, 3.11, 3.12  |
+| Python     | 3.10, 3.11, 3.12, 3.13 | 3.10, 3.11, 3.12, 3.13 |
 | Platform   | AMD64/ARM64(\*)        | AMD64/ARM64(\*)        |
 | Kubernetes | 1.30, 1.31, 1.32, 1.33 | 1.30, 1.31, 1.32, 1.33 |
 | PostgreSQL | 13, 14, 15, 16, 17     | 13, 14, 15, 16, 17     |

generated/PYPI_README.md

@@ -58,7 +58,7 @@ Apache Airflow is tested with:
 
 |            | Main version (dev)     | Stable version (3.0.6) |
 |------------|------------------------|------------------------|
-| Python     | 3.10, 3.11, 3.12, 3.13 | 3.9, 3.10, 3.11, 3.12  |
+| Python     | 3.10, 3.11, 3.12, 3.13 | 3.10, 3.11, 3.12, 3.13 |
 | Platform   | AMD64/ARM64(\*)        | AMD64/ARM64(\*)        |
 | Kubernetes | 1.30, 1.31, 1.32, 1.33 | 1.30, 1.31, 1.32, 1.33 |
 | PostgreSQL | 13, 14, 15, 16, 17     | 13, 14, 15, 16, 17     |