Update CRT to pull in Cognito binding and eventstream crash fix (#324)

Author: bretambrose

sdk/pom.xml

@@ -42,7 +42,7 @@
     <dependency>
       <groupId>software.amazon.awssdk.crt</groupId>
       <artifactId>aws-crt</artifactId>
-      <version>0.19.3</version>
+      <version>0.19.4</version>
     </dependency>
     <dependency>
       <groupId>org.slf4j</groupId>