Consider disabled SSL flag in ConnectionFactoryOptions

[resolves #453][#460]

Author: govi20

src/main/java/io/r2dbc/postgresql/PostgresqlConnectionFactoryProvider.java

@@ -287,7 +287,12 @@ private static PostgresqlConnectionConfiguration.Builder fromConnectionFactoryOp
 
     private static void setupSsl(PostgresqlConnectionConfiguration.Builder builder, OptionMapper mapper) {
 
-        mapper.from(SSL).to(builder::enableSsl);
+        mapper.from(SSL).map(OptionMapper::toBoolean).to(enableSsl -> {
+            if(enableSsl) {
+                builder.enableSsl();
+            }
+        });
+
         mapper.from(SSL_MODE).map(it -> {
 
             if (it instanceof String) {

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

@@ -149,7 +149,22 @@ void supportsWithoutUser() {
     }
 
     @Test
-    void supportsSsl() {
+    void disableSsl() {
+        PostgresqlConnectionFactory factory = this.provider.create(builder()
+            .option(DRIVER, POSTGRESQL_DRIVER)
+            .option(HOST, "test-host")
+            .option(PASSWORD, "test-password")
+            .option(USER, "test-user")
+            .option(SSL, false)
+            .build());
+
+        SSLConfig sslConfig = factory.getConfiguration().getSslConfig();
+
+        assertThat(sslConfig.getSslMode()).isEqualTo(SSLMode.DISABLE);
+    }
+
+    @Test
+    void enableSsl() {
         PostgresqlConnectionFactory factory = this.provider.create(builder()
             .option(DRIVER, POSTGRESQL_DRIVER)
             .option(HOST, "test-host")