chore: update contributing guidelines [skip ci]

Author: aminya

Readme.md

@@ -110,9 +110,22 @@ Benchmark minifyFiles
 
 ### Contributing
 
+You would need to install the ldc compiler for the D programming language
+```
+curl -fsS https://dlang.org/install.sh | bash -s ldc
+```
+After installation, it will print a message about activating it. Something like `source activate_ldc.sh`. 
+
+After running the activation command, clone the repository:
+```
+git clone --recurse-submodules https://github.com/aminya/minijson
+cd minijson
+```
+
+Then build with:
 ```
 pnpm install
-pnpm run build.node
+pnpm build.node
 ```
 
 ### License