Fix new rubocop warnings

lib/bounding_box.rb

@@ -64,7 +64,7 @@ class BoundingBox
 
     if min_lon < -LON_LIMIT || min_lat < -LAT_LIMIT || max_lon > +LON_LIMIT || max_lat > +LAT_LIMIT
       raise OSM::APIBadBoundingBox, "The latitudes must be between #{-LAT_LIMIT} and #{LAT_LIMIT}," \
-                                       " and longitudes between #{-LON_LIMIT} and #{LON_LIMIT}"
+                                    " and longitudes between #{-LON_LIMIT} and #{LON_LIMIT}"
     end
     self
   end

lib/diff_reader.rb

@@ -85,7 +85,7 @@ class DiffReader
       model = MODELS[model_name]
       if model.nil?
         raise OSM::APIBadUserInput, "Unexpected element type #{model_name}, " \
-                                       "expected node, way or relation."
+                                    "expected node, way or relation."
       end
       # new in libxml-ruby >= 2, expand returns an element not associated
       # with a document. this means that there's no encoding parameter,