circup: add page (#6293)

pages/common/circup.md

@@ -0,0 +1,24 @@
+# circup
+
+> The CircuitPython library updater.
+> More information: <https://github.com/adafruit/circup>.
+
+- Interactively update modules on a device:
+
+`circup update`
+
+- Install a new library:
+
+`circup install {{library_name}}`
+
+- Search for a library:
+
+`circup show {{partial_name}}`
+
+- List all libraries on a connected device in `requirements.txt` format:
+
+`circup freeze`
+
+- Save all libraries on a connected device in the current directory:
+
+`circup freeze -r`