Tool builtin:dfu-discovery@0.1.2 already installed
Downloading packages
arduino:arm-none-eabi-gcc@7-2017q4
Failed to install platform: 'arduino:renesas_uno:1.5.2'.
Error: 4 DEADLINE_EXCEEDED: context deadline exceeded
These are the search results on the forum: Search results for 'deadline exceeded order:latest_topic' - Arduino Forum. You'll need to modify the arduino-cli.yaml file in the configuration folder (see instructions in the topics in above search).
You did not mention your operating system; https://support.arduino.cc/hc/en-us/articles/4415103213714-Find-sketches-libraries-board-cores-and-other-files-on-your-computer#boards contains the directories for each operating system; search that page for configuration folder.