Revert "Fix edge case where vcenter is not properly set for diverging norms (…" (#337)

This reverts commit 644e1d0.

Author: beckermr

ultraplot/axes/plot.py

@@ -2707,13 +2707,6 @@ def _parse_cmap(
 
         # Create the continuous normalizer.
         norm = _not_none(norm, "div" if "diverging" in trues else "linear")
-        # If using a diverging norm, fair=True, and vcenter not set, default to midpoint
-        if norm in ("div", "diverging") or "diverging" in trues:
-            fair = norm_kw.get("fair", True)  # defaults to True
-            vcenter = norm_kw.get("vcenter", 0)
-            if fair and vcenter is None and vmin is not None and vmax is not None:
-                vcenter = 0.5 * (vmin + vmax)
-            norm_kw["vcenter"] = vcenter
         if isinstance(norm, mcolors.Normalize):
             norm.vmin, norm.vmax = vmin, vmax
         else:
@@ -2946,6 +2939,7 @@ def _parse_level_lim(
                     f"Incompatible arguments vmin={vmin!r}, vmax={vmax!r}, and "
                     "symmetric=True. Ignoring the latter."
                 )
+
         return vmin, vmax, kwargs
 
     def _parse_level_num(