fix: just use the DateTimeFormatter to parse any datetime value

consumer/junit5/src/test/groovy/au/com/dius/pact/consumer/junit5/DateTimeWithTimezoneTest.groovy

@@ -0,0 +1,42 @@
+package au.com.dius.pact.consumer.junit5
+
+import au.com.dius.pact.consumer.MockServer
+import au.com.dius.pact.consumer.dsl.PactDslJsonBody
+import au.com.dius.pact.consumer.dsl.PactDslWithProvider
+import au.com.dius.pact.core.model.RequestResponsePact
+import au.com.dius.pact.core.model.annotations.Pact
+import org.apache.http.HttpResponse
+import org.apache.http.client.fluent.Request
+import org.apache.http.entity.StringEntity
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.extension.ExtendWith
+
+import java.time.ZonedDateTime
+import java.time.format.DateTimeFormatter
+
+@ExtendWith(PactConsumerTestExt)
+@PactTestFor(providerName = 'ProviderWithDateTime')
+class DateTimeWithTimezoneTest {
+  @Pact(consumer = 'Consumer')
+  RequestResponsePact pactWithTimezone(PactDslWithProvider builder) {
+    builder
+      .uponReceiving('a request with some datetime info')
+        .method('POST')
+        .path('/values')
+        .body(new PactDslJsonBody().datetime('datetime', "YYYY-MM-dd'T'HH:mm:ss.SSSxxx"))
+      .willRespondWith()
+        .status(200)
+        .body(new PactDslJsonBody().datetime('datetime', "YYYY-MM-dd'T'HH:mm:ss.SSSxxx"))
+      .toPact()
+  }
+
+  @Test
+  void testFiles(MockServer mockServer) {
+    HttpResponse httpResponse = Request.Post("${mockServer.url}/values")
+      .body(new StringEntity('{"datetime": "' +
+        DateTimeFormatter.ofPattern("YYYY-MM-dd'T'HH:mm:ss.SSSxxx").format(ZonedDateTime.now())
+        + '"}', 'application/json', 'UTF-8'))
+      .execute().returnResponse()
+    assert httpResponse.statusLine.statusCode == 200
+  }
+}

core/matchers/src/main/kotlin/au/com/dius/pact/core/matchers/MatcherExecutor.kt

@@ -22,8 +22,6 @@ import org.w3c.dom.Text
 import java.math.BigDecimal
 import java.math.BigInteger
 import java.text.ParseException
-import java.time.ZoneId
-import java.time.ZonedDateTime
 import java.time.format.DateTimeFormatter
 import java.time.format.DateTimeParseException
 
@@ -323,7 +321,7 @@ fun <M : Mismatch> matchDateTime(
     emptyList()
   } else {
     try {
-      ZonedDateTime.parse(safeToString(actual), DateTimeFormatter.ofPattern(pattern).withZone(ZoneId.systemDefault()))
+      DateTimeFormatter.ofPattern(pattern).parse(safeToString(actual))
       emptyList<M>()
     } catch (e: DateTimeParseException) {
       listOf(mismatchFactory.create(expected, actual,