GUACAMOLE-1956: Update Duo SDK to latest compatible (1.3.1).

doc/licenses/duo-universal-sdk-1.2.0/dep-coordinates.txt

@@ -1 +0,0 @@
-com.duosecurity:duo-universal-sdk:jar:1.2.0

doc/licenses/duo-universal-sdk-1.3.1/README

@@ -1,8 +1,8 @@
 Duo Universal SDK for Java (https://duo.com/docs/duoweb)
 --------------------------------------------------------
 
-    Version: 1.2.0
+    Version: 1.3.1
     From: 'Cisco Systems'
     License(s):
-        Duo License (bundled/duo-universal-sdk-1.2.0/LICENSE)
+        Duo License (bundled/duo-universal-sdk-1.3.1/LICENSE)
 

doc/licenses/duo-universal-sdk-1.3.1/dep-coordinates.txt

@@ -0,0 +1 @@
+com.duosecurity:duo-universal-sdk:jar:1.3.1

extensions/guacamole-auth-duo/pom.xml

@@ -77,7 +77,7 @@
         <dependency>
             <groupId>com.duosecurity</groupId>
             <artifactId>duo-universal-sdk</artifactId>
-            <version>1.2.0</version>
+            <version>1.3.1</version>
             <exclusions>
                 <exclusion>
                     <groupId>com.squareup.okhttp3</groupId>