perf: speed up self-update by calling /releases/latest api instead of /releases

[vemoo]

Using ReleaseList ends up calling https://api.github.com/repos/jdx/mise/releases but it was only being used to get the latest version.

Now Update is reused which has a get_latest_release that calls https://api.github.com/repos/jdx/mise/releases/latest.

As reference this are the sizes of the responses of each of the endpoints

• https://api.github.com/repos/jdx/mise/releases 2,4M
• https://api.github.com/repos/jdx/mise/releases/latest 77k

This are the results before and after in my case:

before:

➤ time mise self-update
Checking target-arch... mise-v2025.3.2-linux-x64.tar.gz
Checking current version... v2025.3.2
Checking latest released version... mise is already up to date
mise plugin:dotnet   ✓ https://github.com/mise-plugins/mise-dotnet.git#162124c
________________________________________________________
Executed in    7.17 secs      fish           external
   usr time  146.07 millis    0.65 millis  145.42 millis
   sys time   82.81 millis    1.22 millis   81.58 millis

after:

➤ time mise self-update
Checking target-arch... mise-v2025.3.2-linux-x64.tar.gz
Checking current version... v2025.3.2
Checking latest released version... mise is already up to date
mise plugin:dotnet   ✓ https://github.com/mise-plugins/mise-dotnet.git#162124c
________________________________________________________
Executed in    1.96 secs      fish           external
   usr time   67.64 millis  891.00 micros   66.74 millis
   sys time   52.84 millis  939.00 micros   51.90 millis

It still takes longer than what I would expect, considering the time mise upgrade takes:

➤ mise ls --current
Tool   Version  Source                      Requested
bun    1.2.5    ~/.config/mise/config.toml  latest
deno   2.2.3    ~/.config/mise/config.toml  latest
node   22.14.0  ~/.config/mise/config.toml  lts
usage  2.0.5    ~/.config/mise/config.toml  latest
➤ rm -r ~/.cache/mise/
➤ time mise upgrade
mise All tools are up to date

________________________________________________________
Executed in  171.74 millis    fish           external
   usr time   19.08 millis    0.00 micros   19.08 millis
   sys time   17.74 millis  737.00 micros   17.00 millis