Increase max runners for 'linux.g4dn.12xlarge.nvidia.gpu' and 'linux.g5.12xlarge.nvidia.gpu' to 50 (#4489)

Author: jeanschmidt

.github/scale-config.yml

@@ -67,13 +67,13 @@ runner_types:
     disk_size: 150
     instance_type: g4dn.12xlarge
     is_ephemeral: false
-    max_available: 25
+    max_available: 50
     os: linux
   linux.g5.12xlarge.nvidia.gpu:
     disk_size: 150
     instance_type: g5.12xlarge
     is_ephemeral: false
-    max_available: 20
+    max_available: 50
     os: linux
   linux.g5.4xlarge.nvidia.gpu:
     disk_size: 150