Update LLVM version in building_from_source.md

Author: pjuftring

runtime/contributing/building_from_source.md

@@ -65,7 +65,7 @@ functions.
 ```shell
 wget https://apt.llvm.org/llvm.sh
 chmod +x llvm.sh
-./llvm.sh 16
+./llvm.sh 17
 apt install --install-recommends -y cmake libglib2.0-dev
 ```