automation: increase size of Linux AMI build volume

I ran out of space attempting to build a few AMIs. Let's give
the environment an extra 2 GB to utilize.

Differential Revision: https://phab.mercurial-scm.org/D6915

contrib/automation/hgautomation/aws.py

@@ -847,7 +847,7 b' def ensure_linux_dev_ami(c: AWSConnectio'
                 'DeviceName': image.block_device_mappings[0]['DeviceName'],
                 'Ebs': {
                     'DeleteOnTermination': True,
-                    'VolumeSize': 8,
+                    'VolumeSize': 10,
                     'VolumeType': 'gp2',
                 },
             },