caddytls: Add Caddyfile support for `propagation_timeout` (#4178)

* add propagation_timeout to UnmarshalCaddyfile

- Closes #4177

* added caddyfile_adapt test

caddytest/integration/caddyfile_adapt/tls_propagation_timeout.txt

@@ -0,0 +1,70 @@
+localhost
+
+respond "hello from localhost"
+tls {
+	issuer acme {
+		propagation_timeout "10m0s"
+	}
+}
+----------
+{
+	"apps": {
+		"http": {
+			"servers": {
+				"srv0": {
+					"listen": [
+						":443"
+					],
+					"routes": [
+						{
+							"match": [
+								{
+									"host": [
+										"localhost"
+									]
+								}
+							],
+							"handle": [
+								{
+									"handler": "subroute",
+									"routes": [
+										{
+											"handle": [
+												{
+													"body": "hello from localhost",
+													"handler": "static_response"
+												}
+											]
+										}
+									]
+								}
+							],
+							"terminal": true
+						}
+					]
+				}
+			}
+		},
+		"tls": {
+			"automation": {
+				"policies": [
+					{
+						"subjects": [
+							"localhost"
+						],
+						"issuers": [
+							{
+								"challenges": {
+									"dns": {
+										"propagation_timeout": 600000000000
+									}
+								},
+								"module": "acme"
+							}
+						]
+					}
+				]
+			}
+		}
+	}
+}

modules/caddytls/acmeissuer.go

@@ -387,6 +387,22 @@ func (iss *ACMEIssuer) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
 					return err
 				}
 				iss.Challenges.DNS.ProviderRaw = caddyconfig.JSONModuleObject(unm, "name", provName, nil)
+			case "propagation_timeout":
+				if !d.NextArg() {
+					return d.ArgErr()
+				}
+				timeoutStr := d.Val()
+				timeout, err := caddy.ParseDuration(timeoutStr)
+				if err != nil {
+					return d.Errf("invalid propagation_timeout duration %s: %v", timeoutStr, err)
+				}
+				if iss.Challenges == nil {
+					iss.Challenges = new(ChallengesConfig)
+				}
+				if iss.Challenges.DNS == nil {
+					iss.Challenges.DNS = new(DNSChallengeConfig)
+				}
+				iss.Challenges.DNS.PropagationTimeout = caddy.Duration(timeout)
 
 			case "resolvers":
 				if iss.Challenges == nil {