Add flag to disable self-upgrades

[vidplace7]

PlatformIO packaging efforts downstream in Fedora, Debian, Arch, OpenWrt, and probably others must currently patch platformio-core to remove the platformio upgrade command to ensure packaging is not broken. This results in additional maintainer overhead.

Example patch from Fedora: platformio-short-circuit-upgrades.patch
CC: @musicinmybrain

As the maintainer of the OpenWrt PlatformIO package, and adoptive-maintainer of the Debian packaging. This would be greatly appreciated.

Request: Provide build-time flag to disable platformio upgrade command

[musicinmybrain]

CC: @musicinmybrain

I’m only involved in Fedora’s python-platformio package because I have to patch its strict dependency bounds every time I update python-starlette. I have no real interest in the package per se. The “real” maintainer of the Fedora package is @davide125.

[davide125]

Yes, this would be great to have.