Add CircuitPython references

Author: relic-se

1209/3500/index.md

@@ -4,6 +4,9 @@ title: Thumby
 owner: TinyCircuits
 license: MIT
 site: https://tinycircuits.com/products/thumby
-source: https://github.com/TinyCircuits/ASM4008-TinyCircuits-Thumby
+source: https://github.com/relic-se/circuitpython,https://github.com/TinyCircuits/ASM4008-TinyCircuits-Thumby
 ---
 The tiny playable, programmable keychain
+
+Download the latest CircuitPython firmware for this device:
+https://circuitpython.org/board/tinycircuits_thumby/

1209/3501/index.md

@@ -4,6 +4,9 @@ title: Thumby Color
 owner: TinyCircuits
 license: MIT
 site: https://tinycircuits.com/products/thumby-color
-source: https://color.thumby.us/
+source: https://github.com/relic-se/circuitpython,https://color.thumby.us/
 ---
 Next generation of the playable, programmable keychain
+
+Download the latest CircuitPython firmware for this device:
+https://circuitpython.org/board/tinycircuits_thumby_color/