Service file for systemd starts after all networks have gotten IP addresses

Unlike network.target the network-online.target guarantees that the network
devices are online.

If you bind to 0.0.0.0, [::], [::1], and/or 127.0.0.1 only that is enough to
proceed. But in case a particular IP is needed, like ${COREOS_PUBLIC_IPV4},
we require any IP assignments to have completed before Caddy's start. That
is achieved by depending on systemd-networkd-wait-online.service (which is
scheduled before network-online.target, then, automatically).

.gitattributes

+# files for systemd
+*.path    text eol=lf whitespace=blank-at-eol,space-before-tab,tab-in-indent,trailing-space,tabwidth=2
+*.service text eol=lf whitespace=blank-at-eol,space-before-tab,tab-in-indent,trailing-space,tabwidth=2
+*.timer   text eol=lf whitespace=blank-at-eol,space-before-tab,tab-in-indent,trailing-space,tabwidth=2

dist/init/linux-systemd/caddy@.service

@@ -4,7 +4,9 @@
 [Unit]
 Description=Caddy HTTP/2 web server %I
 Documentation=https://caddyserver.com/docs
-After=network.target
+After=network-online.target
+Wants=network-online.target
+Wants=systemd-networkd-wait-online.service
 
 [Service]
 ; run user and group for caddy