Remove Kubernetes 1.26 support (apache#40943)

Co-authored-by: raphaelauv <[email protected]>

README.md

@@ -97,14 +97,14 @@ Airflow is not a streaming solution, but it is often used to process real-time d
 
 Apache Airflow is tested with:
 
-|             | Main version (dev)           | Stable version (2.9.3)     |
-|-------------|------------------------------|----------------------------|
-| Python      | 3.8, 3.9, 3.10, 3.11, 3.12   | 3.8, 3.9, 3.10, 3.11, 3.12 |
-| Platform    | AMD64/ARM64(\*)              | AMD64/ARM64(\*)            |
-| Kubernetes  | 1.26, 1.27, 1.28, 1.29, 1.30 | 1.26, 1.27, 1.28, 1.29     |
-| PostgreSQL  | 12, 13, 14, 15, 16           | 12, 13, 14, 15, 16         |
-| MySQL       | 8.0, 8.4, Innovation         | 8.0, Innovation            |
-| SQLite      | 3.15.0+                      | 3.15.0+                    |
+|            | Main version (dev)         | Stable version (2.9.3)     |
+|------------|----------------------------|----------------------------|
+| Python     | 3.8, 3.9, 3.10, 3.11, 3.12 | 3.8, 3.9, 3.10, 3.11, 3.12 |
+| Platform   | AMD64/ARM64(\*)            | AMD64/ARM64(\*)            |
+| Kubernetes | 1.27, 1.28, 1.29, 1.30     | 1.26, 1.27, 1.28, 1.29     |
+| PostgreSQL | 12, 13, 14, 15, 16         | 12, 13, 14, 15, 16         |
+| MySQL      | 8.0, 8.4, Innovation       | 8.0, Innovation            |
+| SQLite     | 3.15.0+                    | 3.15.0+                    |
 
 \* Experimental
 

dev/breeze/doc/images/output_k8s_configure-cluster.txt

@@ -1 +1 @@
-76afff445df4e4b1ec3f12b247e32cd4
+2a1fe3591ff78e72168154d4bb199b8d

dev/breeze/doc/images/output_k8s_create-cluster.txt

@@ -1 +1 @@
-ad32180d5fae88f4653ec887d978e300
+4866b440eeac112d88193f560da0bdc0

dev/breeze/doc/images/output_k8s_delete-cluster.txt

@@ -1 +1 @@
-2a28f38ac2e74026fd041b1113d1275e
+e0f4a8031c07e030b991fad51ef053e4