add build from source notes to readme and minor bug fix to build_wheel workflow

Author: karosc

.github/workflows/build_wheel.yml

@@ -98,6 +98,7 @@ jobs:
     runs-on: ubuntu-latest
     needs:
       - build_wheels
+      - build_sdist
     steps:
       - name: Download all distribution artifacts
         uses: actions/download-artifact@v5

swmm-toolkit/README.md

@@ -16,7 +16,7 @@
 
 ## Community
 
-[![Discord](https://img.shields.io/badge/Discord-Join%20Chat-7289da?logo=discord&logoColor=white)](https://discord.com/channels/1412143058463756421/1412144907312955532)
+[![Discord](https://img.shields.io/badge/Discord-Join%20Chat-7289da?logo=discord&logoColor=white)](https://discord.gg/U8wqxgjt9C)
 
 Join the discussion!  We will do everything we can to help you!
 
@@ -37,4 +37,23 @@ Run a SWMM simulation.
 from swmm.toolkit import solver
 
 solver.run('input_file.inp', 'report_file.rpt', 'output_file.out')
+
 ```
+
+## Build From Source
+
+> [!NOTE]  
+> Since version version 0.16.1, swmm-toolkit by default has been built and published
+> using the [python stable ABI](https://docs.python.org/3/c-api/stable.html#stable-abi) for 
+> python 3.9 onward. Using the stable ABI introduces very minor performance reduction while 
+> substantially simplifying our release process and compatibility with future python versions.
+> 
+> The commands below show how to build this package with and without using the python stable ABI.
+
+### Build with python stable ABI
+
+` python -m build .`
+
+### Build without python stable ABI
+
+` NO_STABLE_ABI=1 python -m build`