Merge pull request #427 from microsoft/dev/gcampbell/READMeTypo

fix typo in readme

Author: gcampbell-msft

README.md

@@ -15,7 +15,7 @@ If you need any environment variables to be set or any terminal operations to be
 (like the usual `./autogen.sh`, `./configure` or `vcvarsall.bat`), you need to launch VSCode from a terminal
 that is already set up according to your project requirements OR you can point the `makefile.preConfigureSript`
 setting to a batch script file and invoke it at any time via the command `makefile.preconfigure` in the pallette.
-By seting `makefile.alwaysPreConfigure` to true, you don't need to run the pre-configure command separately.
+By setting `makefile.alwaysPreConfigure` to true, you don't need to run the pre-configure command separately.
 The extension is going to invoke the script before every configure operation.
 
 ### Configuring your project