typo

Co-authored-by: Milan Curcic <caomaco@gmail.com>

Author: nshaffer

FortranCon2021-stdlib/stdlib-talk.tex

@@ -228,7 +228,7 @@
 \begin{frame}
   \frametitle{Cross-platform support monitored with Github's CI workflow}
 
-  \begin{block}{Patforms tested on every pull request}
+  \begin{block}{Platforms tested on every pull request}
     \begin{tabular}{llll}
       GNU & 9,10,11 & Ubuntu 20.04 & x86\_64 \\
       GNU & 9,10,11 & macOS 10.15  & x86\_64 \\