fix: pom.xml to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JAVA-ORGAPACHESHIRO-2944236

Author: snyk-bot

pom.xml

@@ -45,7 +45,7 @@
         <pax.exam.version>4.13.1</pax.exam.version>
         <pax.url.version>2.6.2</pax.url.version>
         <pax.jdbc.version>1.3.1</pax.jdbc.version>
-        <shiro.version>1.7.1</shiro.version>
+        <shiro.version>1.9.1</shiro.version>
         <liquibase.version>3.5.5</liquibase.version>
         <snakeyaml.version>1.17</snakeyaml.version>
         <derby.version>10.11.1.1</derby.version>