Recommend the simplest possible configuration and build commands

Once users wish to start customizing their build by potentially
enabling optimizations, then they can learn about such differences.
For now it's not useful to add this extra branch in the instructions.
Let's keep it simple.

Author: ChrisThrasher

README.md

@@ -37,17 +37,10 @@ The template starts out very basic, but might receive additional features over t
 
     Using CMake from the command line is straightforward as well.
 
-    For a single-configuration generator (typically the case on Linux and macOS):
     ```
-    cmake -S . -B build -DCMAKE_BUILD_TYPE=Release
+    cmake -B build
     cmake --build build
     ```
-
-    For a multi-configuration generator (typically the case on Windows):
-    ```
-    cmake -S . -B build
-    cmake --build build --config Release
-    ```
 1. Enjoy!
 
 ## Upgrading SFML