Upgrade Java Mail to 1.5.4

Closes gh-3381
Closes gh-3383

Author: wilkinsona

spring-boot-dependencies/pom.xml

@@ -82,7 +82,7 @@
 		<janino.version>2.6.1</janino.version>
 		<javassist.version>3.18.1-GA</javassist.version> <!-- Same as Hibernate -->
 		<javax-cache.version>1.0.0</javax-cache.version>
-		<javax-mail.version>1.5.3</javax-mail.version>
+		<javax-mail.version>1.5.4</javax-mail.version>
 		<javax-transaction.version>1.2</javax-transaction.version>
 		<jaxen.version>1.1.6</jaxen.version>
 		<jdom2.version>2.0.6</jdom2.version>