Switch to using repo2docker with buildkit for building

Brings in:

repo2docker (among others):
- jupyterhub/repo2docker#1402
- jupyterhub/repo2docker#1413

binderhub:
- jupyterhub/binderhub#1929
- jupyterhub/binderhub#1930

Note that this *could* cause some issues for the very few repos
that depend on internal details of the non buildx old builder.
For example, see scikit-learn/scikit-learn#30835

mybinder/Chart.yaml

@@ -8,7 +8,7 @@ dependencies:
   # Source code:    https://github.com/jupyterhub/binderhub/tree/main/helm-chart
   # App changelog:  https://github.com/jupyterhub/binderhub/blob/main/CHANGES.md
   - name: binderhub
-    version: "1.0.0-0.dev.git.3688.h7031b344"
+    version: "1.0.0-0.dev.git.3704.h3883aac1"
     repository: https://jupyterhub.github.io/helm-chart
     condition: binderhubEnabled
 

mybinder/values.yaml

@@ -217,9 +217,7 @@ binderhub:
             })();
           }
     KubernetesBuildExecutor:
-      build_image: quay.io/jupyterhub/repo2docker:2024.07.0-79.gb0cfd45
-      memory_limit: "6G"
-      memory_request: "2G"
+      build_image: quay.io/jupyterhub/repo2docker:2024.07.0-114.g80d186a
 
   extraConfig:
     # Send Events to StackDriver on Google Cloud