Fix: changed deprecated matplotlib parameter

Summary:
The parameter was renamed in MPL 3.5.0 in 2021, and the deprecated version is no longer supported.

https://matplotlib.org/stable/api/prev_api_changes/api_changes_3.5.0.html#the-first-parameter-of-axes-grid-and-axis-grid-has-been-renamed-to-visible

Reviewed By: bottler

Differential Revision: D46724242

fbshipit-source-id: 04e2ab6d63369d939ea4f0ce7d64693e0b95ee91

pytorch3d/implicitron/tools/stats.py

@@ -434,12 +434,9 @@ class Stats(object):
                 plt.gca().yaxis.label.set_color(c[0:3] * 0.75)
                 plt.legend(tmodes)
                 gcolor = np.array(mcolors.to_rgba("lightgray"))
-                plt.grid(
-                    b=True, which="major", color=gcolor, linestyle="-", linewidth=0.4
-                )
-                plt.grid(
-                    b=True, which="minor", color=gcolor, linestyle="--", linewidth=0.2
-                )
+                grid_params = {"visible": True, "color": gcolor}
+                plt.grid(**grid_params, which="major", linestyle="-", linewidth=0.4)
+                plt.grid(**grid_params, which="minor", linestyle="--", linewidth=0.2)
                 plt.minorticks_on()
 
             plt.tight_layout()