fix: pom.xml to reduce vulnerabilities (#585)

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JAVA-XERCES-608891

Author: snyk-bot

pom.xml

@@ -287,7 +287,7 @@
             <groupId>xerces</groupId>
             <artifactId>xercesImpl</artifactId>
             <!-- Note: CVE-2020-14338) in xercesImpl:2.12.0 but Apache has not released an update to this library yet to eliminate it. See ESAPI-security-bulletin3.pdf for further details. -->
-            <version>2.12.0</version>
+            <version>2.12.1</version>
         </dependency>
         <dependency>
             <groupId>xml-apis</groupId>