test: update mock bar_attrs_relative

* Reduced font size of text "Three" to ensure the baseline image also
  fits the text inside the bar.

Author: n-riesco

test/image/mocks/bar_attrs_relative.json

@@ -3,27 +3,28 @@
         {
             "width":[1,0.8,0.6,0.4],
             "text":[1,2,3333333333,4],
-	    "textposition":"outside",
+            "textposition":"outside",
             "y":[1,2,3,4],
             "x":[1,2,3,4],
             "type":"bar"
         }, {
             "width":[0.4,0.6,0.8,1],
             "text":["Three",2,"outside text",0],
-	    "textposition":"auto",
+            "textposition":"auto",
+            "textfont":[{"size":10}],
             "y":[3,2,1,0],
             "x":[1,2,3,4],
             "type":"bar"
         }, {
             "width":1,
             "text":[-1,-3,-2,-4],
-	    "textposition":"inside",
+            "textposition":"inside",
             "y":[-1,-3,-2,-4],
             "x":[1,2,3,4],
             "type":"bar"
         }, {
             "text":[0,"outside text",-3,-2],
-	    "textposition":"auto",
+            "textposition":"auto",
             "y":[0,-0.25,-3,-2],
             "x":[1,2,3,4],
             "type":"bar"