Update Rust experience

It's been quite some time since I last used Rust, and I never used it
real extensively. So be more honest about that.

cv.tex

@@ -22,7 +22,7 @@
   \hspace*{-0.3cm}\begin{bchart}[max=10,width=3.4cm,plain]
     \bcbar[plain,text=Python]{9}
     \bcbar[plain,text=Java]{7}
-    \bcbar[plain,text=Rust]{6}
+    \bcbar[plain,text=Rust]{5}
     \bcbar[plain,text=C/C++]{7}
   \end{bchart}
   \vspace*{0.5cm}\\