Increase wait time when waiting for server to be created

[Jalle19]

Just got this the first time I tried this plugin:

hcloud output will be in this color.

==> hcloud: Creating temporary ssh key
==> hcloud: Creating new server: packer-hcloud-1540747207
==> hcloud: Created server 1297963
==> hcloud: Waiting for the server to be running...
==> hcloud: waiter timed out
==> hcloud: Waiting for server 1297963 to be destroyed...
==> hcloud: Deleting temporary ssh key...
==> hcloud: Got state error: waiter timed out
Build 'hcloud' errored: waiter timed out

==> Some builds didn't complete successfully and had errors:
--> hcloud: waiter timed out

==> Builds finished but no artifacts were created.