Migrate build scripts to Gradle

tools/build-plugin.sh

@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
-set -e
+set -euo pipefail
 
 # Find project root (one directory above this script)
 SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
@@ -7,8 +7,4 @@ PROJECT_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
 
 cd "$PROJECT_ROOT"
 
-if [[ -x ./mvnw ]]; then
-  ./mvnw package
-else
-  mvn package
-fi
+exec ./gradlew build "$@"