chore: ignore maven-shade-plugin dependency-reduced-pom.xml

The shade plugin writes dependency-reduced-pom.xml next to pom.xml on
every package build. Add it to .gitignore so it stops showing up as
untracked after `mvn package`.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: Vova Kolmakov

.gitignore

@@ -2,6 +2,7 @@ target/
 !.mvn/wrapper/maven-wrapper.jar
 !**/src/main/**/target/
 !**/src/test/**/target/
+dependency-reduced-pom.xml
 
 ### IntelliJ IDEA ###
 .idea