Add SDRplay V3 instructions

Compile-from-source-in-Linux.md

@@ -169,6 +169,13 @@ cmake -Wno-dev -DCMAKE_INSTALL_PREFIX=/opt/install/libmirisdr ..
 make -j $(nproc) install
 </code></pre>
 
+<h3>SDRplay (Using SDRplay's V3 API)</h3>
+Either download the API from: [SDRplay](https://www.sdrplay.com/downloads/) or run:
+<pre><code>git clone https://github.com/srcejon/sdrplayapi.git
+cd sdrplayapi
+sudo install_lib.sh
+</code></pre>
+
 <h3>RTL-SDR</h3>
 
 <pre><code>cd /opt/build