README.md: add public source code location

Author: lerwys

README.md

@@ -4,6 +4,10 @@ LBNL Embedded Ethernet Protocol (LEEP)
 LEEP protocol python implementation and tooling
 used by LBL and partner laboratories.
 
+### Source
+
+https://github.com/BerkeleyLab/leep/
+
 ### Requirements
 
 ```bash
@@ -16,8 +20,14 @@ python3 -m pip install --upgrade build
 python3 -m build
 ```
 
-### Installing
+### Installing from source
+
+```bash
+python3 -m pip install <LEEP directory>
+```
+
+### Installing from PyPI
 
 ```bash
-pip install <LEEP directory>
+python3 -m pip install leep
 ```