Fix integration tests on newer JDKs using a smaller of Instant resolution.

[#572][resolves #571]

Co-authored-by: Francesco Komauli <[email protected]>

Author: fkomauli

src/test/java/io/r2dbc/postgresql/AbstractCodecIntegrationTests.java

@@ -435,7 +435,7 @@ void localDateTime() {
         testCodec(LocalDateTime.class, LocalDateTime.now().truncatedTo(ChronoUnit.MICROS), "TIMESTAMP");
         testCodec(LocalDateTime.class, LocalDateTime.now().truncatedTo(ChronoUnit.MICROS), "TIMESTAMPTZ");
 
-        Instant now = Instant.now();
+        Instant now = Instant.now().truncatedTo(ChronoUnit.MICROS);
         LocalDateTime ldt = now.atZone(ZoneId.systemDefault()).toLocalDateTime();
         testCodec(LocalDateTime.class, ldt, Instant.class, (actual, expected) -> {