Increment TAxis ClassDef version to 11 to fix build

Author: JasMehta08

hist/hist/inc/TAxis.h

@@ -181,7 +181,7 @@ class TAxis : public TNamed, public TAttAxis {
    void               SetRefPad(TVirtualPad *pad);
    Float_t            GetRefLength() const { return fRefLength; }
 
-   ClassDefOverride(TAxis,10)  //Axis class
+   ClassDefOverride(TAxis,11)  //Axis class
 };
 
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