Update gitignore - Eclipse IDE specific conf (#14099)

Those Ecilpse-IDE specific files are generated by mvn eclipse:eclipse.
diff --git a/.gitignore b/.gitignore
index b504f33..a3061c1 100644
--- a/.gitignore
+++ b/.gitignore
@@ -11,6 +11,8 @@
 .settings/
 .project
 .classpath
+.externalToolBuilders
+maven-eclipse.xml
 
 # idea ignore
 .idea/