fix: pom.xml to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JAVA-ORGECLIPSEJETTYHTTP2-5958918
- https://snyk.io/vuln/SNYK-JAVA-ORGXERIALSNAPPY-5710960
- https://snyk.io/vuln/SNYK-JAVA-ORGXERIALSNAPPY-5710959
- https://snyk.io/vuln/SNYK-JAVA-ORGXERIALSNAPPY-5710961
- https://snyk.io/vuln/SNYK-JAVA-ORGECLIPSEJETTY-5958847
- https://snyk.io/vuln/SNYK-JAVA-ORGECLIPSEJETTYHTTP2-5958845
- https://snyk.io/vuln/SNYK-JAVA-ORGECLIPSEJETTY-5902998
- https://snyk.io/vuln/SNYK-JAVA-IONETTY-5725787
- https://snyk.io/vuln/SNYK-JAVA-ORGAPACHESOLR-6241853
- https://snyk.io/vuln/SNYK-JAVA-IONETTY-2812456
- https://snyk.io/vuln/SNYK-JAVA-COMFASTERXMLWOODSTOX-3091135
- https://snyk.io/vuln/SNYK-JAVA-ORGECLIPSEJETTY-2945453
- https://snyk.io/vuln/SNYK-JAVA-ORGECLIPSEJETTY-5426161

pom.xml

@@ -115,7 +115,7 @@
                             </goals>
                             <configuration>
                                 <rules>
-                                    <DependencyConvergence />
+                                    <DependencyConvergence/>
                                 </rules>
                             </configuration>
                         </execution>
@@ -1042,7 +1042,7 @@
             <dependency>
                 <groupId>org.dspace.modules</groupId>
                 <artifactId>additions</artifactId>
-                <version>7.6-SNAPSHOT</version>
+                <version>8.0</version>
             </dependency>
 
             <dependency>