Bump protocol-toolkit-bom from 1.2.0 to 1.2.1 (#953)

Author: dependabot[bot]

pom.xml

@@ -4,7 +4,7 @@
     <parent>
         <groupId>de.rub.nds</groupId>
         <artifactId>protocol-toolkit-bom</artifactId>
-        <version>1.2.0</version>
+        <version>1.2.1</version>
     </parent>
 
     <groupId>de.rub.nds.tls.attacker</groupId>