chore: temporarily stop using maven mirror

#3814 (comment)

Author: mpeddada1

.kokoro/presubmit/downstream-build.sh

@@ -25,9 +25,9 @@ scriptDir=$(realpath "$(dirname "${BASH_SOURCE[0]}")")
 cd "${scriptDir}/../.." # git repo root
 source "$scriptDir/common.sh"
 
-# Use GCP Maven Mirror
-mkdir -p "${HOME}/.m2"
-cp settings.xml "${HOME}/.m2"
+# # Use GCP Maven Mirror
+# mkdir -p "${HOME}/.m2"
+# cp settings.xml "${HOME}/.m2"
 
 # Publish this repo's modules to local maven to make them available for downstream libraries
 mvn install --projects '!gapic-generator-java' \