add information on how to properly update CLI on codespace

[felipemadero]

Is your feature request related to a problem? Please describe.
Currently the following sequence is needed:

killall -9 avalanche
curl -sSfL https://raw.githubusercontent.com/ava-labs/avalanche-cli/main/scripts/install.sh | sudo sh -s -- -b /usr/local/bin

In case the codespace was used to set up a L1, it will be stopped by the former, so you will also need to execute:

avalanche node local start <BlockchainName>-local-node-<NetworkName>

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