Use `plt.subplots`

Instead of two calls to plt functions.

Inst_eddies/Analysis/anim_eddy_contours.py

@@ -154,9 +154,8 @@ if __name__ == "__main__":
         d_max = SHPC.d_init[0] + SHPC.n_dates[0] - 1
     # --
 
-    fig = plt.figure()
     projection = ccrs.PlateCarree()
-    ax = plt.axes(projection=projection)
+    fig, ax = plt.subplots(subplot_kw={"projection": projection})
     ani = anim_eddies(fig, ax, SHPC, args.window, d_min, d_max, args.light)
     ani.save("eddy_contours.gif", writer="imagemagick")