Fix mattermost notification actions

[optik-aper]

Description

Fix notifications after major version update to mattermost action

[github-actions]

Unit Tests and Coverage

Show Output

@vultr/[email protected] test
jest

-----------------------|---------|----------|---------|---------|-------------------

File	% Stmts	% Branch	% Funcs	% Lines	Uncovered Line #s
All files	98.43	95.69	89.65	98.43
src	93.81	94.02	80	93.81
index.js	100	100	100	100
util.js	85	87.5	75	85	66-75,93
src/api	100	100	100	100
account.js	100	100	100	100
applications.js	100	100	100	100
backups.js	100	100	100	100
bare-metal.js	100	100	100	100
billing.js	100	100	100	100
block-storage.js	100	100	100	100
databases.js	100	100	100	100
dns.js	100	100	100	100
firewall.js	100	100	100	100
instances.js	100	100	100	100
iso.js	100	100	100	100
kubernetes.js	100	100	100	100
load-balancers.js	100	100	100	100
object-storage.js	100	100	100	100
operating-systems.js	100	100	100	100
plans.js	100	100	100	100
regions.js	100	100	100	100
registries.js	100	100	100	100
reserved-ips.js	100	100	100	100
snapshots.js	100	100	100	100
ssh-keys.js	100	100	100	100
startup-scripts.js	100	100	100	100
users.js	100	100	100	100
vpc2.js	100	100	100	100
vpcs.js	100	100	100	100
test	100	100	100	100
config.js	100	100	100	100
util.js	100	100	100	100
-----------------------	---------	----------	---------	---------	-------------------

*Pusher: @optik-aper, Action: `pull_request_target`*

[happytreees]

lgtm