Tested 1.0.0-0ubuntu4~18.04.0 on Cosmic:

ubuntu@ip-172-31-7-41:~$ sudo apt install --reinstall ec2-hibinit-agent
Reading package lists... Done
Building dependency tree       
Reading state information... Done
0 upgraded, 0 newly installed, 1 reinstalled, 0 to remove and 0 not upgraded.
Need to get 0 B/10.0 kB of archives.
After this operation, 0 B of additional disk space will be used.
(Reading database ... 111595 files and directories currently installed.)
Preparing to unpack .../ec2-hibinit-agent_1.0.0-0ubuntu4~18.04.0_all.deb ...
Unpacking ec2-hibinit-agent (1.0.0-0ubuntu4~18.04.0) over (1.0.0-0ubuntu4~18.04.0) ...
Setting up ec2-hibinit-agent (1.0.0-0ubuntu4~18.04.0) ...
ubuntu@ip-172-31-7-41:~$ service hibinit-agent status
● hibinit-agent.service - EC2 instance hibernation setup agent
   Loaded: loaded (/lib/systemd/system/hibinit-agent.service; enabled; vendor preset: enabled)
   Active: inactive (dead) since Tue 2019-03-12 14:30:38 UTC; 7s ago
     Docs: file:/usr/share/doc/ec2-hibinit-agent/README

Mar 12 14:30:38 ip-172-31-7-41 /hibinit-agent[1937]: Running: swapoff /swap-hibinit
Mar 12 14:30:38 ip-172-31-7-41 hibinit-agent[1937]: Effective config: {'log_to_syslog': True, 'log_to_stderr': True, 'mkswap': 'mkswap {swapfile}', 'swapon': 'swapon {swapfil
Mar 12 14:30:38 ip-172-31-7-41 hibinit-agent[1937]: Will check if swap is at least: 4000 megabytes
Mar 12 14:30:38 ip-172-31-7-41 hibinit-agent[1937]: There's sufficient swap available (have 4194304000, need 4194304000)
Mar 12 14:30:38 ip-172-31-7-41 hibinit-agent[1937]: Running: swapon /swap-hibinit
Mar 12 14:30:38 ip-172-31-7-41 hibinit-agent[1937]: Updating the kernel offset for the swapfile: /swap-hibinit
Mar 12 14:30:38 ip-172-31-7-41 hibinit-agent[1937]: Setting swap device to 51713 with offset 235520
Mar 12 14:30:38 ip-172-31-7-41 hibinit-agent[1937]: Done updating the swap offset. Turning swapoff
Mar 12 14:30:38 ip-172-31-7-41 hibinit-agent[1937]: Running: swapoff /swap-hibinit
Mar 12 14:30:38 ip-172-31-7-41 systemd[1]: Started EC2 instance hibernation setup agent.
ubuntu@ip-172-31-7-41:~$  grep resume /boot/grub/grub.cfg 
        linux	/boot/vmlinuz-4.15.0-1034-aws root=UUID=b5361850-7320-445b-b1c9-a8b294830484 ro  console=tty1 console=ttyS0 nvme.io_timeout=4294967295 no_console_suspend=1 resume_offset=235520 resume=/dev/xvda1
	        linux	/boot/vmlinuz-4.15.0-1034-aws root=UUID=b5361850-7320-445b-b1c9-a8b294830484 ro  console=tty1 console=ttyS0 nvme.io_timeout=4294967295 no_console_suspend=1 resume_offset=235520 resume=/dev/xvda1
	        linux	/boot/vmlinuz-4.15.0-1033-aws root=UUID=b5361850-7320-445b-b1c9-a8b294830484 ro  console=tty1 console=ttyS0 nvme.io_timeout=4294967295 no_console_suspend=1 resume_offset=235520 resume=/dev/xvda1
	        linux	/boot/vmlinuz-4.15.0-1007-aws root=UUID=b5361850-7320-445b-b1c9-a8b294830484 ro  console=tty1 console=ttyS0 nvme.io_timeout=4294967295 no_console_suspend=1 resume_offset=235520 resume=/dev/xvda1
ubuntu@ip-172-31-7-41:~$ sudo apt purge ec2-hibinit-agent
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages will be REMOVED:
  ec2-hibinit-agent*
0 upgraded, 0 newly installed, 1 to remove and 0 not upgraded.
After this operation, 59.4 kB disk space will be freed.
Do you want to continue? [Y/n]  
(Reading database ... 111595 files and directories currently installed.)
Removing ec2-hibinit-agent (1.0.0-0ubuntu4~18.04.0) ...
(Reading database ... 111582 files and directories currently installed.)
Purging configuration files for ec2-hibinit-agent (1.0.0-0ubuntu4~18.04.0) ...
Sourcing file `/etc/default/grub'
Sourcing file `/etc/default/grub.d/50-cloudimg-settings.cfg'
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-4.15.0-1034-aws
Found initrd image: /boot/initrd.img-4.15.0-1034-aws
Found linux image: /boot/vmlinuz-4.15.0-1033-aws
Found initrd image: /boot/initrd.img-4.15.0-1033-aws
Found linux image: /boot/vmlinuz-4.15.0-1007-aws
Found initrd image: /boot/initrd.img-4.15.0-1007-aws
done
ubuntu@ip-172-31-7-41:~$ grep resume /boot/grub/grub.cfg 
ubuntu@ip-172-31-7-41:~$ 

The first hibernation/resume cycle succeeded, but the second failed. The failure seems do be due to a kernel issue since the ACPI events are not seen after the resume.

Since the package seems to be working well I'm marking the verification as successful.