Fixed wrong step number

Author: Causeless

README.md

@@ -93,7 +93,7 @@ For unspecified versions assume compatibility with the latest ubuntu LTS release
 
 5. (optional) `sudo ninja install -C build` (To uninstall later, keep the build directory intact. The game can then be uninstalled by `sudo ninja uninstall -C build`)
 
-If you want to change the buildtype afterwards, you can use `meson configure --buildtype {release or debug}` in the build directory or create a secondary build directory as in Step 4. There are also additional build options documented in the [wiki](https://github.com/cortex-command-community/Cortex-Command-Community-Project-Source/wiki/Meson-build-options) as well as through running `meson configure` in the build directory.
+If you want to change the buildtype afterwards, you can use `meson configure --buildtype {release or debug}` in the build directory or create a secondary build directory as in Step 3. There are also additional build options documented in the [wiki](https://github.com/cortex-command-community/Cortex-Command-Community-Project-Source/wiki/Meson-build-options) as well as through running `meson configure` in the build directory.
 
 ## Running
 (If you installed the game in step 5 above, it should appear with your regular applications and will just run)