incusd/migration: Update protobuf #36

Job	Run time
Documentation tests	10m 9s
Code tests	8m 51s
System tests (1.18.x, cluster, dir)	13m 7s
System tests (1.18.x, cluster, btrfs)	13m 5s
System tests (1.18.x, cluster, lvm)	15m 15s
System tests (1.18.x, cluster, zfs)	17m 49s
System tests (1.18.x, cluster, ceph)	20m 28s
System tests (1.18.x, cluster, random)	13m 39s
System tests (1.18.x, standalone, dir)	25m 24s
System tests (1.18.x, standalone, btrfs)	24m 15s
System tests (1.18.x, standalone, lvm)	42m 53s
System tests (1.18.x, standalone, zfs)	39m 30s
System tests (1.18.x, standalone, ceph)	1h 9m 11s
System tests (1.18.x, standalone, random)	30m 55s
System tests (stable, cluster, dir)	11m 54s
System tests (stable, standalone, dir)	20m 34s
System tests (tip, cluster, dir)	12m 48s
System tests (tip, standalone, dir)	21m 40s
Client tests (1.18.x, ubuntu-latest)	58s
Client tests (1.18.x, macos-latest)	1m 10s
Client tests (1.18.x, windows-latest)	2m 34s
	6h 56m 9s

Provide feedback