Update colorbar tests

Author: seisman

pygmt/tests/baseline/test_colorbar_shading_list.png.dvc

@@ -1,5 +1,5 @@
 outs:
-- md5: 9a5c688d4b6270cf8823333f7857d47e
-  size: 21912
+- md5: 52364ac84db033b53f7125ce12e95cce
+  size: 25000
   path: test_colorbar_shading_list.png
   hash: md5

pygmt/tests/test_colorbar.py

@@ -22,6 +22,6 @@ def test_colorbar_shading_list():
     Create colorbar and set shading by passing the high/low values as a list.
     """
     fig = Figure()
-    fig.basemap(region=[0, 10, 0, 10], projection="X8c", frame="a")
+    fig.basemap(region=[0, 10, 0, 2], projection="X10c/2c", frame="a")
     fig.colorbar(cmap="geo", shading=[-0.7, 0.2], frame=True)
     return fig