Upgrade to emsdk 3.1.73 InstallationAndUsage.rst

Author: mcbarton

docs/source/InstallationAndUsage.rst

@@ -51,14 +51,14 @@ These instructions will assume you have cmake installed on your system. First cl
     cd ./xeus-cpp
 
 
-You'll now want to make sure you're using emsdk version "3.1.45" and activate it. You can get this by executing the following
+You'll now want to make sure you're using emsdk version "3.1.73" and activate it. You can get this by executing the following
 
 .. code-block:: bash
     cd $HOME
     git clone https://github.com/emscripten-core/emsdk.git
     cd emsdk
-    ./emsdk install 3.1.45
-    ./emsdk activate 3.1.45
+    ./emsdk install 3.1.73
+    ./emsdk activate 3.1.73
     source $HOME/emsdk/emsdk_env.sh