gh-actions: Also build for Teensy3.1

Signed-off-by: Daniel Schaefer <dhs@frame.work>

Author: JohnAZoidberg

.github/workflows/build.yml

@@ -39,12 +39,15 @@ jobs:
         patch -d ~/.platformio/ -p0 < diff/teensy3/yield.cpp.diff
 
         # Teensy4.1
-        patch -d ~/.platformio/ -p0 < diff/arduino.py.diff || true
         patch -d ~/.platformio/ -p0 < diff/teensy4/usb_desc.c.diff
         patch -d ~/.platformio/ -p0 < diff/teensy4/usb_desc.h.diff
         patch -d ~/.platformio/ -p0 < diff/teensy4/usb_inst.cpp.diff
         patch -d ~/.platformio/ -p0 < diff/teensy4/yield.cpp.diff
 
+    - name: Build for Teensy 3.1
+      run: |
+        pio run -e teensy31
+
     - name: Build for Teensy 3.6
       run: |
         pio run -e teensy36