Remove unused import

Author: bh-tt

lib/src/main/java/com/diffplug/spotless/cpp/ClangFormatStep.java

@@ -20,7 +20,6 @@
 import java.io.Serializable;
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.List;
 import java.util.Objects;