Workaround bug in xcolor.sty

The bug seems to be fixed in xcolor 2.12, released one month after Ubuntu 16.04.
Of course, the Ubuntu-provided packages disable `tlmgr` so no updating TeXlive.
And this is why I don't like it when distros repackage sub-distros…

https://tex.stackexchange.com/questions/274524/definecolorset-of-xcolor-problem-with-color-values-starting-with-f

pharo-titlepage.sty

@@ -32,14 +32,14 @@
     \expandafter\def\csname pgf@sh@pi@current page\endcsname{pgfpageorigin}}
 \pgfkeys{/tikz/overlay/.add code={}{\setpagenode}}
 
-\definecolor{PharoBlue}{HTML}{2b98d8}
-\definecolor{PharoDarkBlue}{HTML}{164c6c}
-\definecolor{PharoRed}{HTML}{a10b0b}
+\definecolor{PharoBlue}{HTML}{2B98D8}
+\definecolor{PharoDarkBlue}{HTML}{164C6C}
+\definecolor{PharoRed}{HTML}{A10B0B}
 
-\definecolor{BeaconOrange}{HTML}{f7931e}
-\definecolor{BeaconRed}{HTML}{ed1c24}
+\definecolor{BeaconOrange}{HTML}{F7931E}
+\definecolor{BeaconRed}{HTML}{ED1C24}
 
-\definecolor{LightShade}{HTML}{eeeeee}
+\definecolor{LightShade}{HTML}{EEEEEE}
 
 \pgfdeclarelayer{background}
 \pgfsetlayers{background,main}