Bump plugin from 4.50 to 4.51 (#110)

Author: dependabot[bot]

pom.xml

@@ -4,7 +4,7 @@
     <parent>
         <groupId>org.jenkins-ci.plugins</groupId>
         <artifactId>plugin</artifactId>
-        <version>4.50</version>
+        <version>4.51</version>
         <relativePath />
     </parent>